Add exception for Bulgarian to mk_hyb_file

The Bulgarian hyphenation patterns contain a line consisting of '0ь0'
which has no practical effect on hyphenation. Add an exception in
roundtrip testing to make sure we don't fail while comparing our tables
with the input data.

Test: make -j works and creates .hyb files for bg and cu
Change-Id: Ia46b8a45fe522f5194d8105d31b34b0e27528cc9
(cherry picked from commit 6308ea4c4b)

engine/src/flutter/tools/mk_hyb_file.py

@@ -539,6 +539,12 @@ def verify_hyb_file(hyb_fn, pat_fn, chr_fn, hyp_fn):
     patterns = []
     exceptions = []
     traverse_trie(0, '', trie_data, ch_map, pattern_data, patterns, exceptions)
+
+    # EXCEPTION for Bulgarian (bg), which contains an ineffectual line of <0, U+044C, 0>
+    if u'\u044c' in patterns:
+        patterns.remove(u'\u044c')
+        patterns.append(u'0\u044c0')
+
     assert verify_file_sorted(patterns, pat_fn), 'pattern table not verified'
     assert verify_file_sorted(exceptions, hyp_fn), 'exception table not verified'