[Sanitizers][Test] XFAIL array cookie tests on arm (#154031)

Poisoning of C++ array redzones is only implemented for x86 CPUs. New
arm64 bots are being brought up, where these test fail.

Original C++ arrays shadow poisoning change:

http://reviews.llvm.org/D4774

rdar://158025391

Co-authored-by: Mariusz Borsa <[email protected]>

Author: wrotki

compiler-rt/test/asan/TestCases/Posix/new_array_cookie_test.cpp

@@ -6,6 +6,9 @@
 
 // UNSUPPORTED: ios
 
+// Poisoning C++ array redzones is not implemented on arm
+// XFAIL: target=arm{{.*}}
+
 #include <stdio.h>
 #include <stdlib.h>
 struct C {

compiler-rt/test/asan/TestCases/Posix/new_array_cookie_uaf_test.cpp

@@ -5,6 +5,9 @@
 
 // UNSUPPORTED: ios
 
+// Poisoning C++ array redzones is not implemented on arm
+// XFAIL: target=arm{{.*}}
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <assert.h>