ICU-13837 c build: make --disable-layoutex the default

- update GitHub workflow / Azure pipeline to no longer specify layoutex

Also:
- update configure.ac that was missed in #1265 cad3903cc25c0db7f392adbc024829aea6591a50 ICU-21051
- some FALSE/TRUE were missed in source/test/letest
diff --git a/.ci-builds/.azure-pipelines.yml b/.ci-builds/.azure-pipelines.yml
index 478f0a1..e9411cb 100644
--- a/.ci-builds/.azure-pipelines.yml
+++ b/.ci-builds/.azure-pipelines.yml
@@ -90,7 +90,7 @@
       lfs: true
       fetchDepth: 10
     - script: |
-        export CXXFLAGS="-std=c++14 -Winvalid-constexpr" && cd icu4c/source && ./runConfigureICU --enable-debug --disable-release Linux --disable-layout --disable-layoutex && make -j2 check
+        export CXXFLAGS="-std=c++14 -Winvalid-constexpr" && cd icu4c/source && ./runConfigureICU --enable-debug --disable-release Linux && make -j2 check
       displayName: 'Build and Test C++14'
       env:
         CC: clang
diff --git a/.ci-builds/.azure-valgrind.yml b/.ci-builds/.azure-valgrind.yml
index 6b00e56..866fcbf 100644
--- a/.ci-builds/.azure-valgrind.yml
+++ b/.ci-builds/.azure-valgrind.yml
@@ -47,7 +47,7 @@
       displayName: 'Install valgrind'
       timeoutInMinutes: 5
     - script: |
-        cd icu4c/source && ./runConfigureICU --enable-debug Linux --disable-renaming --disable-layout --disable-layoutex && make -j2 tests
+        cd icu4c/source && ./runConfigureICU --enable-debug Linux --disable-renaming && make -j2 tests
       displayName: 'Build'
       timeoutInMinutes: 10
       env:
diff --git a/.github/workflows/icu_ci.yml b/.github/workflows/icu_ci.yml
index 9e67b09..d905aa89 100644
--- a/.github/workflows/icu_ci.yml
+++ b/.github/workflows/icu_ci.yml
@@ -47,7 +47,7 @@
         run: |
           sudo apt-get -y install doxygen;
           cd icu4c/source;
-          ./runConfigureICU Linux --enable-layoutex=no;
+          ./runConfigureICU Linux;
           make -j 2;
           make -j 2 check;
           ( cd test/depstest && python3 depstest.py ../../../source/ );
diff --git a/icu4c/source/configure b/icu4c/source/configure
index d5d57ce..0dea6a5 100755
--- a/icu4c/source/configure
+++ b/icu4c/source/configure
@@ -1455,7 +1455,7 @@
   --enable-weak-threads   weakly reference the threading library default=no
   --enable-extras         build ICU extras default=yes
   --enable-icuio          build ICU's icuio library default=yes
-  --enable-layoutex         build ICU's Paragraph Layout library default=yes.
+  --enable-layoutex         build ICU's Paragraph Layout library default=no.
             icu-le-hb must be installed via pkg-config. See http://harfbuzz.org
 
   --enable-tools         build ICU's tools default=yes
@@ -7702,7 +7702,7 @@
 		*) as_fn_error $? "bad value ${enableval} for --enable-layoutex" "$LINENO" 5 ;;
 		esac
 else
-  layoutex=$have_icu_le_hb
+  layoutex=false
 fi
 
 
diff --git a/icu4c/source/configure.ac b/icu4c/source/configure.ac
index 1796ca0..425fdc7 100644
--- a/icu4c/source/configure.ac
+++ b/icu4c/source/configure.ac
@@ -1101,14 +1101,14 @@
 
 # Enable/disable layoutex
 AC_ARG_ENABLE(layoutex,
-	[  --enable-layoutex         build ICU's Paragraph Layout library [default=yes].
+	[  --enable-layoutex         build ICU's Paragraph Layout library [default=no].
             icu-le-hb must be installed via pkg-config. See http://harfbuzz.org],
 	[case "${enableval}" in
 		yes) layoutex=$have_icu_le_hb ;;
 		no)  layoutex=false ;;
 		*) AC_MSG_ERROR(bad value ${enableval} for --enable-layoutex) ;;
 		esac],
-	layoutex=$have_icu_le_hb)
+	layoutex=false)
 ICU_CONDITIONAL(LAYOUTEX, test "$layoutex" = true)
 
 # Enable/disable layout
@@ -1399,6 +1399,7 @@
 		test/perf/ubrkperf/Makefile \
 		test/perf/charperf/Makefile \
 		test/perf/convperf/Makefile \
+		test/perf/localecanperf/Makefile \
 		test/perf/normperf/Makefile \
 		test/perf/DateFmtPerf/Makefile \
 		test/perf/howExpensiveIs/Makefile \
diff --git a/icu4c/source/test/letest/PortableFontInstance.cpp b/icu4c/source/test/letest/PortableFontInstance.cpp
index 26c7fbd..7743fd6 100644
--- a/icu4c/source/test/letest/PortableFontInstance.cpp
+++ b/icu4c/source/test/letest/PortableFontInstance.cpp
@@ -394,7 +394,7 @@
 
 le_bool PortableFontInstance::getGlyphPoint(LEGlyphID /*glyph*/, le_int32 /*pointNumber*/, LEPoint &/*point*/) const
 {
-    return FALSE;
+    return false;
 }
 
 le_int32 PortableFontInstance::getUnitsPerEM() const
diff --git a/icu4c/source/test/letest/SimpleFontInstance.cpp b/icu4c/source/test/letest/SimpleFontInstance.cpp
index 5c46103..e387b08 100644
--- a/icu4c/source/test/letest/SimpleFontInstance.cpp
+++ b/icu4c/source/test/letest/SimpleFontInstance.cpp
@@ -135,6 +135,6 @@
 
 le_bool SimpleFontInstance::getGlyphPoint(LEGlyphID /*glyph*/, le_int32 /*pointNumber*/, LEPoint &/*point*/) const
 {
-    return FALSE;
+    return false;
 }
 
diff --git a/icu4c/source/test/letest/cmaps.cpp b/icu4c/source/test/letest/cmaps.cpp
index 382799a..cb38504 100644
--- a/icu4c/source/test/letest/cmaps.cpp
+++ b/icu4c/source/test/letest/cmaps.cpp
@@ -58,7 +58,7 @@
     le_uint16 i;
     le_uint16 nSubtables = SWAPW(cmap->numberSubtables);
     const CMAPEncodingSubtable *subtable = NULL;
-    le_bool found = FALSE;
+    le_bool found = false;
     le_uint16 foundPlatformID = 0xFFFF;
     le_uint16 foundPlatformSpecificID = 0xFFFF;
     le_uint32 foundOffset = 0;
@@ -76,7 +76,7 @@
                 foundOffset = SWAPL(esh->encodingOffset);
                 foundPlatformID = platformID;
                 foundPlatformSpecificID = platformSpecificID;
-                found = TRUE;
+                found = true;
                 foundTable = i;
                 break;
 
@@ -106,7 +106,7 @@
             foundPlatformID = platformID;
             foundPlatformSpecificID = platformSpecificID;
             foundTable = i;
-            found = TRUE;
+            found = true;
             break;
 
           default: printf("Error: table %d (psid %d) is unknown. Skipping.\n", i, platformSpecificID); break;