Fix test tail with mjit options for clang provided by Xcode 16

```
clang: error: unknown argument '-emit-pch'; did you mean '-Xclang -emit-pch'?
MJIT warning: Making precompiled header failed on compilation. Stopping MJIT worker...
Successful MJIT finish
```

1 files changed, 1 insertions, 0 deletions

diff --git a/mjit.c b/mjit.c
index 031599672e..3200ee2621 100644
--- a/mjit.c
+++ b/mjit.c
@@ -586,6 +586,7 @@ make_pch(void)
 {
     const char *rest_args[] = {
 # ifdef __clang__
+        "-Xclang",
         "-emit-pch",
         "-c",
 # endif