Allow [a-\d] in RegExp parser.

test/cctest/test-regexp.cc

Index: test/cctest/test-regexp.cc
diff --git a/test/cctest/test-regexp.cc b/test/cctest/test-regexp.cc
index 210e5bb0f96dcba2d382f4a63c8c21ca7db5829a..558003f79e7a17051c180cd01ac9270112377e26 100644
--- a/test/cctest/test-regexp.cc
+++ b/test/cctest/test-regexp.cc
@@ -126,6 +126,7 @@ TEST(Parser) {
   CHECK_PARSE_EQ("[x\\dz]", "[x 0-9 z]");
   CHECK_PARSE_EQ("[\\d-z]", "[0-9 - z]");
   CHECK_PARSE_EQ("[\\d-\\d]", "[0-9 - 0-9]");
+  CHECK_PARSE_EQ("[z-\\d]", "[z - 0-9]");
   CHECK_PARSE_EQ("\\cj\\cJ\\ci\\cI\\ck\\cK",
                  "'\\x0a\\x0a\\x09\\x09\\x0b\\x0b'");
   CHECK_PARSE_EQ("\\c!", "'c!'");
@@ -275,8 +276,6 @@ TEST(Errors) {
   const char* kUnterminatedCharacterClass = "Unterminated character class";
   ExpectError("[", kUnterminatedCharacterClass);
   ExpectError("[a-", kUnterminatedCharacterClass);
-  const char* kIllegalCharacterClass = "Illegal character class";
-  ExpectError("[a-\\w]", kIllegalCharacterClass);
   const char* kEndControl = "\\c at end of pattern";
   ExpectError("\\c", kEndControl);
   const char* kNothingToRepeat = "Nothing to repeat";