[EXPERIMENTAL] Revert mte-ffi changes

Partially reverts commit 40311c4.

Author: jieyouxu

tests/run-make/mte-ffi/bar.h

@@ -1,5 +1,3 @@
-// FIXME(#141600) the mte-ffi test doesn't fail in aarch64-gnu
-
 #ifndef __BAR_H
 #define __BAR_H
 

tests/run-make/mte-ffi/bar_float.c

@@ -3,9 +3,9 @@
 #include <stdint.h>
 #include "bar.h"
 
-extern void foo(float*);
+extern void foo(char*);
 
-void bar(float *ptr) {
+void bar(char *ptr) {
     if (((uintptr_t)ptr >> 56) != 0x1f) {
         fprintf(stderr, "Top byte corrupted on Rust -> C FFI boundary!\n");
         exit(1);

tests/run-make/mte-ffi/bar_int.c

@@ -5,7 +5,7 @@
 
 extern void foo(unsigned int *);
 
-void bar(unsigned int *ptr) {
+void bar(char *ptr) {
     if (((uintptr_t)ptr >> 56) != 0x1f) {
         fprintf(stderr, "Top byte corrupted on Rust -> C FFI boundary!\n");
         exit(1);

tests/run-make/mte-ffi/bar_string.c

@@ -1,7 +1,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>
-#include <string.h>
 #include "bar.h"
 
 extern void foo(char*);
@@ -33,7 +32,7 @@ int main(void)
 
     // Store an arbitrary tag in bits 56-59 of the pointer (where an MTE tag may be),
     // and a different value in the ignored top 4 bits.
-    ptr = (char *)((uintptr_t)ptr | 0x1fl << 56);
+    ptr = (unsigned int *)((uintptr_t)ptr | 0x1fl << 56);
 
     if (mte_enabled()) {
         set_tag(ptr);