[asan] Fix odr_c_test failure with gold linker

[bruening]

Summary

Adds another global to asan's odr_c_test to help force the target global to
not lie at the start of bss with the gold linker where it is always
aligned.

[samsonov]

LGTM

[bruening]

I am not yet an LLVM committer. Could you submit this patch on my behalf? Thank you.

[samsonov]

Submitted as r262678.

test/asan/TestCases/Linux/odr_c_test.c

 // Test that we can properly report an ODR violation
 // between an instrumented global and a non-instrumented global.
 
 // RUN: %clang_asan %s -fPIC -shared -o %t-1.so  -DFILE1
 // RUN: %clang_asan %s -fPIC -shared -o %t-2.so  -DFILE2
 // RUN: %clang_asan %s -fPIE %t-1.so %t-2.so -Wl,-R`pwd` -o %t
 // RUN: not %run %t 2>&1 | FileCheck %s
 //
 // REQUIRES: x86_64-target-arch
 //
 // CHECK: The following global variable is not properly aligned.
 // CHECK: ERROR: AddressSanitizer: odr-violation
 #if defined(FILE1)
 __attribute__((aligned(8))) int x;
 __attribute__((aligned(1))) char y;
+// The gold linker puts ZZZ at the start of bss (where it is aligned)
+// unless we have a large alternative like Displace:
+__attribute__((aligned(1))) char Displace[105];
 __attribute__((aligned(1))) char ZZZ[100];
 #elif defined(FILE2)
 int ZZZ = 1;
 #else
 extern int ZZZ;
 int main() {
   return ZZZ;
 }
 #endif