Fix mbstring fuzzer

mb_ereg can throw now, so we need a dummy frame and need to
free the exception afterwards.

Author: nikic

sapi/fuzzer/fuzzer-mbstring.c

@@ -39,6 +39,8 @@ int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
 		return 0;
 	}
 
+	fuzzer_setup_dummy_frame();
+
 	args[0] = data;
 	args[1] = "test123";
 	fuzzer_call_php_func("mb_ereg", 2, args);
@@ -55,7 +57,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
 	args[1] = data;
 	fuzzer_call_php_func("mb_eregi", 2, args);
 
-	php_request_shutdown(NULL);
+	fuzzer_request_shutdown();
 
 	free(data);
 #else