Fix FileCheck --check-prefix lines.

Various tests had sprung up over the years which had --check-prefix=ABC on the
RUN line, but "CHECK-ABC:" later on. This happened to work before, but was
strictly incorrect. FileCheck is getting stricter soon though.

Patch by Ron Ofir.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@188174 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGenObjC/ivar-layout-array0-struct.m b/test/CodeGenObjC/ivar-layout-array0-struct.m
index 267f947..e4d9594 100644
--- a/test/CodeGenObjC/ivar-layout-array0-struct.m
+++ b/test/CodeGenObjC/ivar-layout-array0-struct.m
@@ -1,6 +1,6 @@
 // REQUIRES: x86-64-registered-target
 // RUN: %clang_cc1 -fobjc-gc -triple x86_64-apple-darwin -fobjc-runtime=macosx-fragile-10.5 -O0 -S %s -o %t-64.s
-// RUN: FileCheck -check-prefix LP64 --input-file=%t-64.s %s
+// RUN: FileCheck -check-prefix CHECK-LP64 --input-file=%t-64.s %s
 
 // rdar://8800513
 @interface NSObject {