Fix CodeGen/pgo-sample-thinlto-summary.c with old PM

[thopre]

Summary

Re-add -fexperimental-new-pass-manager to
Clang::CodeGen/pgo-sample-thinlto-summary.c for the test to work on
builds that still default to the old pass manager.

[tejohnson]

lgtm. And I just was informed in a recent review of one of my patches that we are now removing old PM tests, so if you want you could also go ahead and remove the first 2 lines here.

[thopre]

Remove old PM tests

clang/test/CodeGen/pgo-sample-thinlto-summary.c

-// RUN: %clang_cc1 -mllvm -debug-pass=Structure -O2 -fno-experimental-new-pass-manager -fprofile-sample-use=%S/Inputs/pgo-sample-thinlto-summary.prof %s -emit-llvm -o - 2>&1 | FileCheck %s -check-prefix=SAMPLEPGO-OLDPM
-// RUN: %clang_cc1 -mllvm -debug-pass=Structure -O2 -fno-experimental-new-pass-manager -fprofile-sample-use=%S/Inputs/pgo-sample-thinlto-summary.prof %s -emit-llvm -flto=thin -o - 2>&1 | FileCheck %s -check-prefix=THINLTO-OLDPM
-// RUN: %clang_cc1 -fdebug-pass-manager -O2 -fprofile-sample-use=%S/Inputs/pgo-sample-thinlto-summary.prof %s -emit-llvm -o - 2>&1 | FileCheck %s -check-prefix=SAMPLEPGO
-// RUN: %clang_cc1 -fdebug-pass-manager -O2 -fprofile-sample-use=%S/Inputs/pgo-sample-thinlto-summary.prof %s -emit-llvm -flto=thin -o - 2>&1 | FileCheck %s -check-prefix=THINLTO
+// RUN: %clang_cc1 -fexperimental-new-pass-manager -fdebug-pass-manager -O2 -fprofile-sample-use=%S/Inputs/pgo-sample-thinlto-summary.prof %s -emit-llvm -o - 2>&1 | FileCheck %s -check-prefix=SAMPLEPGO
+// RUN: %clang_cc1 -fexperimental-new-pass-manager -fdebug-pass-manager -O2 -fprofile-sample-use=%S/Inputs/pgo-sample-thinlto-summary.prof %s -emit-llvm -flto=thin -o - 2>&1 | FileCheck %s -check-prefix=THINLTO
 
 int baz(int);
 int g;
 
 void foo(int n) {
   for (int i = 0; i < n; i++)
     g += baz(i);
 }

 // thinlto compile.
 // SAMPLEPGO-LABEL: define {{(dso_local )?}}void @bar
 // THINLTO-LABEL: define {{(dso_local )?}}void @bar
 // SAMPLEPGO-NOT: call{{.*}}foo
 // THINLTO: call{{.*}}foo
 void bar(int n) {
   for (int i = 0; i < n; i++)
     foo(i);
-}
+}