[hwasan] add test for global overflow.

[fmayer]

Fix name.

[pcc]

I think we already have a test for this (global.c).

[fmayer]

Sorry, somehow missed the existing test.

compiler-rt/test/hwasan/TestCases/global-buffer-overflow.c

+// RUN: %clang_hwasan  %s -o %t
+// RUN: not %run %t 40 2>&1 | FileCheck %s --check-prefixes=CHECK40
+// RUN: not %run %t 80 2>&1 | FileCheck %s --check-prefixes=CHECK80
+// RUN: not %run %t -30 2>&1 | FileCheck %s --check-prefixes=CHECKm30
+
+// Global access faults do not get reported properly on x86.
+// XFAIL: x86_64
+
+// REQUIRES: stable-runtime
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <sanitizer/hwasan_interface.h>
+
+static volatile char sink;
+
+int main(int argc, char **argv) {
+  __hwasan_enable_allocator_tagging();
+  static char buf[30];
+  int offset = argc < 2 ? 40 : atoi(argv[1]);
+  fprintf(stderr, "base: %p access: %p\n", buf, &buf[offset]);
+  sink = buf[offset];
+
+// CHECK40: is located 10 bytes to the right of 30-byte global
+//
+// CHECK80: is located 50 bytes to the right of 30-byte global
+//
+// CHECKm30: is located 30 bytes to the left of 30-byte global
+}