Fix unexpected flipping when double quotes or comments exist in selectors

Port of wikimedia/node-cssjanus#53, required for v2.0.0.

Author: Krinkle

src/CSSJanus.php

@@ -101,7 +101,7 @@ private static function buildPatterns() {
 		// Use "*+" instead of "*?" to avoid reaching the backtracking limit.
 		// <https://github.com/cssjanus/php-cssjanus/issues/14>, <https://phabricator.wikimedia.org/T215746#4944830>.
 		$patterns['url_chars'] = "(?:{$patterns['url_special_chars']}|{$patterns['nonAscii']}|{$patterns['escape']})*+";
-		$patterns['lookahead_not_open_brace'] = "(?!({$patterns['nmchar']}|\\r?\\n|\s|#|\:|\.|\,|\+|>|\(|\)|\[|\]|=|\*=|~=|\^=|'[^']*'])*+{)";
+		$patterns['lookahead_not_open_brace'] = "(?!({$patterns['nmchar']}|\\r?\\n|\s|#|\:|\.|\,|\+|>|\(|\)|\[|\]|=|\*=|~=|\^=|'[^']*'|\"[^\"]*\"|" . self::TOKEN_COMMENT . ")*+{)";
 		$patterns['lookahead_not_closing_paren'] = "(?!{$patterns['url_chars']}{$patterns['valid_after_uri_chars']}\))";
 		$patterns['lookahead_for_closing_paren'] = "(?={$patterns['url_chars']}{$patterns['valid_after_uri_chars']}\))";
 		$patterns['noflip_single'] = "/({$patterns['noflip_annotation']}{$patterns['lookahead_not_open_brace']}[^;}]+;?)/i";