[clang/test] Run thinlto-clang-diagnostic-handler-in-be.c on x86

Clang test CodeGen/thinlto-clang-diagnostic-handler-in-be.c fails on
some non x86 targets, e.g. hexagon. Since the test already requires x86
to be available as a target this commit forces the target to x86_64.

Reviewed By: steven_wu

Differential Revision: https://reviews.llvm.org/D107667

clang/test/CodeGen/thinlto-clang-diagnostic-handler-in-be.c

@@ -3,11 +3,11 @@
 // REQUIRES: x86-registered-target
 
 // RUN: llvm-profdata merge -o %t1.profdata %S/Inputs/thinlto_expect1.proftext
-// RUN: %clang -O2 -fexperimental-new-pass-manager -flto=thin -g -fprofile-use=%t1.profdata -c -o %t1.bo %s
+// RUN: %clang -target x86_64-linux-gnu -O2 -fexperimental-new-pass-manager -flto=thin -g -fprofile-use=%t1.profdata -c -o %t1.bo %s
 // RUN: llvm-lto -thinlto -o %t %t1.bo
-// RUN: %clang -cc1 -O2 -fexperimental-new-pass-manager -x ir %t1.bo -fthinlto-index=%t.thinlto.bc -emit-obj -Rpass-analysis=info 2>&1 | FileCheck %s -check-prefix=CHECK-REMARK
+// RUN: %clang -cc1 -triple x86_64-linux-gnu -O2 -fexperimental-new-pass-manager -x ir %t1.bo -fthinlto-index=%t.thinlto.bc -emit-obj -Rpass-analysis=info 2>&1 | FileCheck %s -check-prefix=CHECK-REMARK
 // RUN: llvm-profdata merge -o %t2.profdata %S/Inputs/thinlto_expect2.proftext
-// RUN: %clang -cc1 -O2 -fexperimental-new-pass-manager -x ir %t1.bo -fthinlto-index=%t.thinlto.bc -fprofile-instrument-use-path=%t2.profdata -emit-obj 2>&1 | FileCheck %s -allow-empty -check-prefix=CHECK-NOWARNING
+// RUN: %clang -cc1 -triple x86_64-linux-gnu -O2 -fexperimental-new-pass-manager -x ir %t1.bo -fthinlto-index=%t.thinlto.bc -fprofile-instrument-use-path=%t2.profdata -emit-obj 2>&1 | FileCheck %s -allow-empty -check-prefix=CHECK-NOWARNING
 
 int sum;
 __attribute__((noinline)) void bar() {