ICU-21096 adjust logKnownIssues for ICU rbbitst
diff --git a/icu4c/source/test/intltest/rbbitst.cpp b/icu4c/source/test/intltest/rbbitst.cpp
index d5728bd..1cac149 100644
--- a/icu4c/source/test/intltest/rbbitst.cpp
+++ b/icu4c/source/test/intltest/rbbitst.cpp
@@ -1326,34 +1326,37 @@
         const UChar *fString;
     } badTestCases[] = {
         {"10666", "GraphemeBreakTest.txt", u"\u0020\u0020\u0033"},    // Fake example, for illustration.
+        // The following tests were originally for
         // Issue 8151, move the Finnish tailoring of the line break of hyphens to root.
-        // This probably ultimately wants to be resolved by updating UAX-14, but in the mean time
-        // ICU is out of sync with Unicode.
-        {"8151",  "LineBreakTest.txt", u"-#"},
-        {"8151",  "LineBreakTest.txt", u"\u002d\u0308\u0023"},
-        {"8151",  "LineBreakTest.txt", u"\u002d\u00a7"},
-        {"8151",  "LineBreakTest.txt", u"\u002d\u0308\u00a7"},
-        {"8151",  "LineBreakTest.txt", u"\u002d\U00050005"},
-        {"8151",  "LineBreakTest.txt", u"\u002d\u0308\U00050005"},
-        {"8151",  "LineBreakTest.txt", u"\u002d\u0e01"},
-        {"8151",  "LineBreakTest.txt", u"\u002d\u0308\u0e01"},
+        // However, that ticket has been closed as fixed but these tests still fail, so
+        // ICU-21097 has been created to investigate and address these remaining issues.
+        {"21097",  "LineBreakTest.txt", u"-#"},
+        {"21097",  "LineBreakTest.txt", u"\u002d\u0308\u0023"},
+        {"21097",  "LineBreakTest.txt", u"\u002d\u00a7"},
+        {"21097",  "LineBreakTest.txt", u"\u002d\u0308\u00a7"},
+        {"21097",  "LineBreakTest.txt", u"\u002d\U00050005"},
+        {"21097",  "LineBreakTest.txt", u"\u002d\u0308\U00050005"},
+        {"21097",  "LineBreakTest.txt", u"\u002d\u0e01"},
+        {"21097",  "LineBreakTest.txt", u"\u002d\u0308\u0e01"},
 
-        // Issue ICU-12017 Improve line break around numbers
-        {"12017", "LineBreakTest.txt", u"\u002C\u0030"},   // ",0"
-        {"12017", "LineBreakTest.txt", u"\u002C\u0308\u0030"},
-        {"12017", "LineBreakTest.txt", u"find .com"},
-        {"12017", "LineBreakTest.txt", u"equals .35 cents"},
-        {"12017", "LineBreakTest.txt", u"a.2 "},
-        {"12017", "LineBreakTest.txt", u"a.2 \u0915"},
-        {"12017", "LineBreakTest.txt", u"a.2 \u672C"},
-        {"12017", "LineBreakTest.txt", u"a.2\u3000\u672C"},
-        {"12017", "LineBreakTest.txt", u"a.2\u3000\u307E"},
-        {"12017", "LineBreakTest.txt", u"a.2\u3000\u0033"},
-        {"12017", "LineBreakTest.txt", u"A.1 \uBABB"},
-        {"12017", "LineBreakTest.txt", u"\uBD24\uC5B4\u002E\u0020\u0041\u002E\u0032\u0020\uBCFC"},
-        {"12017", "LineBreakTest.txt", u"\uBD10\uC694\u002E\u0020\u0041\u002E\u0033\u0020\uBABB"},
-        {"12017", "LineBreakTest.txt", u"\uC694\u002E\u0020\u0041\u002E\u0034\u0020\uBABB"},
-        {"12017", "LineBreakTest.txt", u"a.2\u3000\u300C"},
+        // The following tests were originally for
+        // Issue ICU-12017 Improve line break around numbers.
+        // However, that ticket has been closed as fixed but these tests still fail, so
+        // ICU-21097 has been created to investigate and address these remaining issues.
+        {"21097", "LineBreakTest.txt", u"\u002C\u0030"},   // ",0"
+        {"21097", "LineBreakTest.txt", u"\u002C\u0308\u0030"},
+        {"21097", "LineBreakTest.txt", u"equals .35 cents"},
+        {"21097", "LineBreakTest.txt", u"a.2 "},
+        {"21097", "LineBreakTest.txt", u"a.2 \u0915"},
+        {"21097", "LineBreakTest.txt", u"a.2 \u672C"},
+        {"21097", "LineBreakTest.txt", u"a.2\u3000\u672C"},
+        {"21097", "LineBreakTest.txt", u"a.2\u3000\u307E"},
+        {"21097", "LineBreakTest.txt", u"a.2\u3000\u0033"},
+        {"21097", "LineBreakTest.txt", u"A.1 \uBABB"},
+        {"21097", "LineBreakTest.txt", u"\uBD24\uC5B4\u002E\u0020\u0041\u002E\u0032\u0020\uBCFC"},
+        {"21097", "LineBreakTest.txt", u"\uBD10\uC694\u002E\u0020\u0041\u002E\u0033\u0020\uBABB"},
+        {"21097", "LineBreakTest.txt", u"\uC694\u002E\u0020\u0041\u002E\u0034\u0020\uBABB"},
+        {"21097", "LineBreakTest.txt", u"a.2\u3000\u300C"},
     };
 
     for (int n=0; n<UPRV_LENGTHOF(badTestCases); n++) {