[regexp] implement case-insensitive unicode regexps.

test/mjsunit/mjsunit.status

 # Copyright 2012 the V8 project authors. All rights reserved.
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 # modification, are permitted provided that the following conditions are
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 #
 #     * Redistributions of source code must retain the above copyright
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@@ skipping 271 matching lines @@
   'regress/regress-1200351': [PASS, ['mode == debug', SLOW]],
   'regress/regress-crbug-474297': [PASS, ['mode == debug', SLOW]],
   'strong/implicit-conversions': [PASS, SLOW],
   'strong/load-element-mutate-backing-store': [PASS, SLOW],
 
   # TODO(titzer): correct WASM adapter frame alignment on arm64
   'wasm/*': [PASS, ['arch == arm64', SKIP]],
 
   # TODO(titzer): SSE 4.1 required for asm-wasm test (floor).
   'wasm/asm-wasm': [SKIP],
+
+    # case-insensitive unicode regexp relies on case mapping provided by ICU.
+  'harmony/unicode-regexp-ignore-case': [PASS, ['no_i18n == True', FAIL]],
 }],  # ALWAYS
 
 ['novfp3 == True', {
   'asm/embenchen/box2d': [SKIP],
   'asm/embenchen/zlib': [SKIP],
   'asm/embenchen/memops': [SKIP],
   'asm/embenchen/lua_binarytrees': [SKIP],
 }],  # novfp3 == True
 
 ##############################################################################
@@ skipping 840 matching lines @@
   # Tests taking too long.
   'array-functions-prototype-misc': [SKIP],
   'strong/implicit-conversions': [SKIP],
   'strong/load-element-mutate-backing-store': [SKIP],
 
   # Stack overflow.
   'big-array-literal': [SKIP],
 }],  # 'gcov_coverage'
 
 ]