[lit] For the "case-insensitive-filesystem" make sure to create the test temporary file
in the test output directory.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@167193 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/lit.cfg b/test/lit.cfg
index 3cbe013..e91e660 100644
--- a/test/lit.cfg
+++ b/test/lit.cfg
@@ -228,7 +228,7 @@
 
 # Case-insensitive file system
 def is_filesystem_case_insensitive():
-    handle, path = tempfile.mkstemp(prefix='case-test')
+    handle, path = tempfile.mkstemp(prefix='case-test', dir=config.test_exec_root)
     isInsensitive = os.path.exists(path.upper())
     os.close(handle)
     os.remove(path)