Update fontchain_linter.py to support more flags.

Android Q will support all region flags in UNSUPPORTED_FLAGS list.
BL - Saint Barthélemy
BQ - Caribbean Netherlands
MQ - Martinique
RE - Réunion
TF - French Southern Territories

Bug: 127811703
Test: Verified on device.
Test: m fontchain_lint
Test: minikin_tests --gtest_filter=EmojiTest.cpp
Test: atest cts/tests/tests/text/src/android/text/cts/EmojiTest.java
Test: atest frameworks/base/core/tests/coretests/src/android/text/EmojiTest.java
Change-Id: Ice1fb10af35dc4e180735d9712167b71635920da

tools/fonts/fontchain_linter.py

@@ -490,11 +490,6 @@ def remove_emoji_exclude(source, items):
 def flag_sequence(territory_code):
     return tuple(0x1F1E6 + ord(ch) - ord('A') for ch in territory_code)
 
-UNSUPPORTED_FLAGS = frozenset({
-    flag_sequence('BL'), flag_sequence('BQ'), flag_sequence('MQ'),
-    flag_sequence('RE'), flag_sequence('TF'),
-})
-
 EQUIVALENT_FLAGS = {
     flag_sequence('BV'): flag_sequence('NO'),
     flag_sequence('CP'): flag_sequence('FR'),
@@ -600,9 +595,6 @@ def compute_expected_emoji():
     for first, second in SAME_FLAG_MAPPINGS:
         equivalent_emoji[first] = second
 
-    # Remove unsupported flags
-    all_sequences.difference_update(UNSUPPORTED_FLAGS)
-
     # Add all tag characters used in flags
     sequence_pieces.update(range(0xE0030, 0xE0039 + 1))
     sequence_pieces.update(range(0xE0061, 0xE007A + 1))