Fix formatting in test function definition

Author: winstonallo

tests/assembly-llvm/regparm-module-flag.rs

@@ -11,7 +11,7 @@ unsafe extern "C" {
 }
 
 #[unsafe(no_mangle)]
-pub unsafe extern "C" fn entrypoint(len: usize, val: i32, ptr: *mut c_void)  -> *mut c_void {
+pub unsafe extern "C" fn entrypoint(len: usize, val: i32, ptr: *mut c_void) -> *mut c_void {
     unsafe { memset(ptr, val, len) }
 }