LibJS+LibRegex: Don't repeat regex match in regexp_exec()

LibRegex already implements this loop in a more performant way, so all
LibJS has to do here is to return things in the right shape, and not
loop over the input string.
Previously this was a quadratic operation on string length, which lead
to crazy execution times on failing regexps - now it's nice and fast :^)

Note that a Regex test has to be updated to remove the stateful flag as
it repeats matching on multiple strings.

1 files changed, 3 insertions, 1 deletions

diff --git a/Tests/LibRegex/Regex.cpp b/Tests/LibRegex/Regex.cpp
index 2e498811b5..c7e699c194 100644
--- a/Tests/LibRegex/Regex.cpp
+++ b/Tests/LibRegex/Regex.cpp
@@ -984,7 +984,9 @@ TEST_CASE(negative_lookahead)
 {
     {
         // Negative lookahead with more than 2 forks difference between lookahead init and finish.
-        Regex<ECMA262> re(":(?!\\^\\)|1)", ECMAScriptFlags::Global);
+        auto options = ECMAScriptOptions { ECMAScriptFlags::Global };
+        options.reset_flag((ECMAScriptFlags)regex::AllFlags::Internal_Stateful);
+        Regex<ECMA262> re(":(?!\\^\\)|1)", options);
         EXPECT_EQ(re.match(":^)").success, false);
         EXPECT_EQ(re.match(":1").success, false);
         EXPECT_EQ(re.match(":foobar").success, true);