clang/test/Misc/ast-dump-decl.c: Add triple. __thread is not supported on all targets.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@170645 91177308-0d34-0410-b5e6-96231b3b80d8

test/Misc/ast-dump-decl.c

-// RUN: %clang_cc1 -ast-dump -ast-dump-filter Test %s | FileCheck -check-prefix CHECK -strict-whitespace %s
-// RUN: %clang_cc1 -ast-dump %s | FileCheck -check-prefix CHECK-TU -strict-whitespace %s
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -ast-dump -ast-dump-filter Test %s | FileCheck -check-prefix CHECK -strict-whitespace %s
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -ast-dump %s | FileCheck -check-prefix CHECK-TU -strict-whitespace %s
 
 int TestLocation;
 // CHECK: VarDecl 0x{{[^ ]*}} <{{.*}}:4:1, col:5> TestLocation