llvm-cov.test: Resurrect part of r194694 for win32 hosts.

llvm-svn: 196207
diff --git a/llvm/test/tools/llvm-cov/llvm-cov.test b/llvm/test/tools/llvm-cov/llvm-cov.test
index 55af86e..83d139d 100644
--- a/llvm/test/tools/llvm-cov/llvm-cov.test
+++ b/llvm/test/tools/llvm-cov/llvm-cov.test
@@ -3,7 +3,7 @@
 REQUIRES: shell
 
 RUN: llvm-cov -gcno=test.gcno -gcda=test.gcda
-RUN: diff test.cpp.gcov test.cpp.llcov
+RUN: diff -aub test.cpp.gcov test.cpp.llcov
 RUN: rm test.cpp.llcov
 
 RUN: not llvm-cov -gcno=test_read_fail.gcno -gcda=test.gcda