remove an old xfailed test

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36810 91177308-0d34-0410-b5e6-96231b3b80d8

test/Transforms/InstCombine/2006-05-10-InvalidIndexUndef.ll

@@ -1,9 +0,0 @@
-; RUN: llvm-upgrade < %s | llvm-as | opt -instcombine | llvm-dis | grep undef
-; XFAIL: *
-
-%str = constant [4 x ubyte] c"str\00"
-
-ubyte %main() {
-        %A = load ubyte* getelementptr ([4 x ubyte]* %str, long 0, long 5)
-        ret ubyte %A
-}