Test-add for static dispatch — `#jni_static_call(s32)(env, cls,
"max", "(II)I", 3, 7)` exercises GetStaticMethodID + CallStaticIntMethod
plus two integer args. Today the lowering bails on `is_static = true`
with `LLVMGetUndef`. IR snapshot captures the placeholder.
The next commit:
- Adds `Jni.GetStaticMethodID` (113), `Jni.CallStaticVoidMethod` (141),
`Jni.CallStaticIntMethod` (129), etc. to the constants struct.
- Wires the static path: skip `GetObjectClass` (`target` IS the
jclass), `NewGlobalRef(target)` to cache it, `GetStaticMethodID`
for the method, then `CallStatic<Type>Method` per return type.