Change default method of disabling JIT https://wiki.php.net/rfc/jit_config_defaults Closes GH-12678
Improve jit tests Closes GH-12425
Don't optimize MUL into SHIFT if we have to check for overflow
Skip 64-bit related tests on 32-bit platforms
Moved tests from ext/opcache/tests/jit/arm64 to ext/opcache/tests/jit