ScriptRegexp::match(): gracefully fail if regexp.exec() throws.

LayoutTests/fast/js/script-tests/regexp-match-exception.js

+description("This tests that ScriptRegexp matching fails when running into an exceptional condition (stack overflow) without crashing.");
+
+function runTest() {
+    var input = document.createElement("input");
+    input.type = "email";
+
+    function repeatedlySet(r) {
+        // Consume stack until failure.
+        input.value = r;
+        repeatedlySet(r);
+    }
+    repeatedlySet("an@example.com");
+}
+shouldThrow("runTest()");