[compiler-rt][tests] Make this test case pass on AArch64 (#117628)

See also D92832 and GCC bug
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80878

Author: pawosm-arm

compiler-rt/test/builtins/Unit/atomic_test.c

@@ -144,7 +144,7 @@ typedef uint64_t maxuint_t;
 
 #define LEN(array) (sizeof(array) / sizeof(array[0]))
 
-__attribute__((aligned(16))) static const char data[] = {
+__attribute__((aligned(16))) static char data[] = {
     0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
     0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
     0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,