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/extended-block-signature-encode.m b/test/CodeGenObjC/extended-block-signature-encode.m
index a380856..3db31fa 100644
--- a/test/CodeGenObjC/extended-block-signature-encode.m
+++ b/test/CodeGenObjC/extended-block-signature-encode.m
@@ -1,5 +1,5 @@
 // RUN: %clang_cc1 -fblocks -triple x86_64-apple-darwin -fencode-extended-block-signature -emit-llvm %s -o - | FileCheck %s
-// RUN: %clang_cc1 -fblocks -triple x86_64-apple-darwin -emit-llvm %s -o - | FileCheck %s -check-prefix=BRIEF
+// RUN: %clang_cc1 -fblocks -triple x86_64-apple-darwin -emit-llvm %s -o - | FileCheck %s -check-prefix=CHECK-BRIEF
 // rdar://12109031
 
 @class NSString, NSArray;