Revert r243752, it broke running tests on OS X (PR24491).

git-svn-id: https://llvm.org/svn/llvm-project/libcxxabi/trunk@245325 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/lit.cfg b/test/lit.cfg
index e10dfe1..ae46288 100644
--- a/test/lit.cfg
+++ b/test/lit.cfg
@@ -53,11 +53,6 @@
 
 config.test_exec_root = os.path.join(obj_root, 'test')
 
-# Check if we have produced a Clang with this build (in-tree)
-this_clang = os.path.join(obj_root, '../../bin/clang++')
-if os.path.exists(this_clang):
-    config.cxx_under_test = this_clang
-
 cfg_variant = getattr(config, 'configuration_variant', 'libcxxabi')
 if cfg_variant:
     print 'Using configuration variant: %s' % cfg_variant