[regexp] Fold repeated assertions

test/cctest/test-regexp.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 296 matching lines @@
   CheckParseEq("[\\118]", "[\\x09 8]");
   CheckParseEq("[\\111]", "[I]");
   CheckParseEq("[\\1111]", "[I 1]");
   CheckParseEq("\\x34", "'\x34'");
   CheckParseEq("\\x60", "'\x60'");
   CheckParseEq("\\x3z", "'x3z'");
   CheckParseEq("\\c", "'\\c'");
   CheckParseEq("\\u0034", "'\x34'");
   CheckParseEq("\\u003z", "'u003z'");
   CheckParseEq("foo[z]*", "(: 'foo' (# 0 - g [z]))");
+  CheckParseEq("^^^$$$\\b\\b\\b\\b", "(: @^i @$i @b)");
+  CheckParseEq("\\b\\b\\b\\b\\B\\B\\B\\B\\b\\b\\b\\b", "(: @b @B @b)");
+  CheckParseEq("\\b\\B\\b", "(: @b @B @b)");
 
   // Unicode regexps
   CheckParseEq("\\u{12345}", "'\\ud808\\udf45'", true);
   CheckParseEq("\\u{12345}\\u{23456}", "(! '\\ud808\\udf45' '\\ud84d\\udc56')",
                true);
   CheckParseEq("\\u{12345}|\\u{23456}", "(| '\\ud808\\udf45' '\\ud84d\\udc56')",
                true);
   CheckParseEq("\\u{12345}{3}", "(# 3 3 g '\\ud808\\udf45')", true);
   CheckParseEq("\\u{12345}*", "(# 0 - g '\\ud808\\udf45')", true);
 
@@ skipping 1698 matching lines @@
   v8::Local<v8::String> external =
       v8::String::NewExternalOneByte(isolate, new UncachedExternalString())
           .ToLocalChecked();
   CHECK(v8::Utils::OpenHandle(*external)->map() ==
         CcTest::i_isolate()->heap()->short_external_one_byte_string_map());
   v8::Local<v8::Object> global = env->Global();
   global->Set(env.local(), v8_str("external"), external).FromJust();
   CompileRun("var re = /y(.)/; re.test('ab');");
   ExpectString("external.substring(1).match(re)[1]", "z");
 }