X86: move test requiring X86TargetLowering info into its own directory

If LLVM is built without X86 as a supported target then the test would
mysteriously fail.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@201668 91177308-0d34-0410-b5e6-96231b3b80d8

test/Transforms/CodeGenPrepare/X86/lit.local.cfg

@@ -0,0 +1,4 @@
+targets = set(config.root.targets_to_build.split())
+if not 'X86' in targets:
+    config.unsupported = True
+