Add inline(never) attribute to musttail test functions

This ensures the test remains robust against optimization passes
that might otherwise inline the functions and obscure the tail
call behavior we're testing.

Author: semtexzv

tests/codegen/tail-call-musttail.rs

@@ -8,6 +8,7 @@
 
 // CHECK-LABEL: define {{.*}}@simple_tail_call(
 #[no_mangle]
+#[inline(never)]
 pub fn simple_tail_call(n: i32) -> i32 {
     // CHECK: musttail call {{.*}}@simple_tail_call(
     // CHECK-NEXT: ret i32
@@ -20,6 +21,7 @@ pub fn simple_tail_call(n: i32) -> i32 {
 
 // CHECK-LABEL: define {{.*}}@tail_call_with_args(
 #[no_mangle]
+#[inline(never)]
 pub fn tail_call_with_args(a: i32, b: i32, c: i32) -> i32 {
     // CHECK: musttail call {{.*}}@tail_call_with_args(
     // CHECK-NEXT: ret i32