Suppress llvm-cov.test on Win32, with REQUIRES: shell

"cd" is unsupported in lit internal runner.

llvm-svn: 194652
diff --git a/llvm/test/tools/llvm-cov/llvm-cov.test b/llvm/test/tools/llvm-cov/llvm-cov.test
index cf694a4..01539da 100644
--- a/llvm/test/tools/llvm-cov/llvm-cov.test
+++ b/llvm/test/tools/llvm-cov/llvm-cov.test
@@ -1,4 +1,6 @@
 RUN: cd %p/Inputs
+# "cd" is unsupported in lit internal runner.
+REQUIRES: shell
 
 RUN: llvm-cov -gcno=test.gcno -gcda=test.gcda \
 RUN:   | diff test.cpp.gcov -