Bugfix in InlineSpiller::traceSiblingValue().

Properly determine whether or not a phi was added by splitting.
Check against the current VNInfo of OrigLI instead of against the
OrigVNI argument.

Patch provided by Jonas Paulsson. Reviewed by Quentin Colombet.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224009 91177308-0d34-0410-b5e6-96231b3b80d8