ICU-21284 Deal with remaining unit normalization TODOs

See #1580
diff --git a/icu4c/source/i18n/measunit_impl.h b/icu4c/source/i18n/measunit_impl.h
index 0f5aac4..645e821 100644
--- a/icu4c/source/i18n/measunit_impl.h
+++ b/icu4c/source/i18n/measunit_impl.h
@@ -130,8 +130,9 @@ struct U_I18N_API SingleUnitImpl : public UMemory {
         if (index > other.index) {
             return 1;
         }
-        // TODO(icu-units#70): revisit when fixing normalization. For now we're
-        // sorting binary prefixes before SI prefixes, as per enum values order.
+        // TODO: revisit if the spec dictates prefix sort order - it doesn't
+        // currently. For now we're sorting binary prefixes before SI prefixes,
+        // as per enum values order.
         if (unitPrefix < other.unitPrefix) {
             return -1;
         }
diff --git a/icu4c/source/test/intltest/measfmttest.cpp b/icu4c/source/test/intltest/measfmttest.cpp
index c9f6b42..e5dfcbb 100644
--- a/icu4c/source/test/intltest/measfmttest.cpp
+++ b/icu4c/source/test/intltest/measfmttest.cpp
@@ -4050,7 +4050,7 @@ void MeasureFormatTest::TestIdentifiers() {
         {"kilogram-per-meter-per-second", "kilogram-per-meter-second"},
         {"kilometer-per-second-per-megaparsec", "kilometer-per-megaparsec-second"},
 
-        // TODO(ICU-21284): Add more test cases once the proper ranking is available.
+        // Correct order of units, as per unitQuantities in CLDR's units.xml
         {"newton-meter", "newton-meter"},
         {"meter-newton", "newton-meter"},
         {"pound-force-foot", "pound-force-foot"},
@@ -4237,11 +4237,6 @@ void MeasureFormatTest::TestParseBuiltIns() {
             continue;
         }
 
-        // TODO(ICU-21284,icu-units#70): fix normalization. Until then, ignore:
-        if (uprv_strcmp(unit.getIdentifier(), "pound-force-foot") == 0) continue;
-        if (uprv_strcmp(unit.getIdentifier(), "kilowatt-hour") == 0) continue;
-        if (uprv_strcmp(unit.getIdentifier(), "newton-meter") == 0) continue;
-
         // Prove that all built-in units are parseable, except "generic" temperature:
         MeasureUnit parsed = MeasureUnit::forIdentifier(unit.getIdentifier(), status);
         if (unit == MeasureUnit::getGenericTemperature()) {
diff --git a/icu4j/main/classes/core/src/com/ibm/icu/impl/units/SingleUnitImpl.java b/icu4j/main/classes/core/src/com/ibm/icu/impl/units/SingleUnitImpl.java
index dd66d74..dd976cb 100644
--- a/icu4j/main/classes/core/src/com/ibm/icu/impl/units/SingleUnitImpl.java
+++ b/icu4j/main/classes/core/src/com/ibm/icu/impl/units/SingleUnitImpl.java
@@ -122,8 +122,9 @@ int compareTo(SingleUnitImpl other) {
         if (index > other.index) {
             return 1;
         }
-        // TODO(icu-units#70): revisit when fixing normalization. For now we're
-        // sorting binary prefixes before SI prefixes, for consistency with ICU4C.
+        // TODO: revisit if the spec dictates prefix sort order - it doesn't
+        // currently. For now we're sorting binary prefixes before SI prefixes,
+        // as per ICU4C's enum values order.
         if (this.getPrefix().getBase() < other.getPrefix().getBase()) {
             return 1;
         }
diff --git a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/format/MeasureUnitTest.java b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/format/MeasureUnitTest.java
index e7e28d1..eda3f75 100644
--- a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/format/MeasureUnitTest.java
+++ b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/format/MeasureUnitTest.java
@@ -3689,7 +3689,7 @@ class TestCase {
             new TestCase("kilogram-per-meter-per-second", "kilogram-per-meter-second"),
             new TestCase("kilometer-per-second-per-megaparsec", "kilometer-per-megaparsec-second"),
 
-            // TODO(ICU-21284): Add more test cases once the proper ranking is available.
+            // Correct order of units, as per unitQuantities in CLDR's units.xml
             new TestCase("newton-meter", "newton-meter"),
             new TestCase("meter-newton", "newton-meter"),
             new TestCase("pound-force-foot", "pound-force-foot"),
@@ -3872,11 +3872,6 @@ public void TestParseBuiltIns() {
                 continue;
             }
 
-            // TODO(ICU-21284,icu-units#70): fix normalization. Until then, ignore:
-            if (unit.getIdentifier() == "pound-force-foot") continue;
-            if (unit.getIdentifier() == "kilowatt-hour") continue;
-            if (unit.getIdentifier() == "newton-meter") continue;
-
             // Prove that all built-in units are parseable, except "generic" temperature:
             if (unit == MeasureUnit.GENERIC_TEMPERATURE) {
                 try {