Add -fno-experimental-pass-manager to make clear which pass manager

we're running and to make flipping the default not regress testing.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@374840 91177308-0d34-0410-b5e6-96231b3b80d8

test/Misc/loop-opt-setup.c

@@ -1,5 +1,5 @@
 // RUN: %clang -O1 -fexperimental-new-pass-manager -fno-unroll-loops -S -o - %s -emit-llvm | FileCheck %s
-// RUN: %clang -O1 -fno-unroll-loops -S -o - %s -emit-llvm | FileCheck %s
+// RUN: %clang -O1 -fno-experimental-new-pass-manager -fno-unroll-loops -S -o - %s -emit-llvm | FileCheck %s
 extern int a[16];
 int b = 0;
 int foo(void) {