One-line addition to the `call_method_offset` switch in
`emit_llvm.zig` — `.s32 => 49` (CallIntMethod). The 1.17 caching
infrastructure handles the rest: GetObjectClass → NewGlobalRef →
GetMethodID populate the shared `@SX_JNI_{CLS,MID}_<key>` pair on
miss; per-call lowering loads the cached jmethodID and dispatches
through vtable slot 49 with an `i32` return.
IR snapshot at `tests/expected/ffi-jni-call-04-jint-return.ir`
updated: the `ret i32 undef` placeholder is replaced by the full
lazy-cache + CallIntMethod sequence keyed on
`("getCount", "()I")`. Pre-1.18 snapshot was 1d7ea72.
ebcfe4c4dc