Remove a pointless assertion.

FindNodeOrInsertPos() is called 10 lines earlier already, and the function
early-returns there if the result is != 0. InsertPos isn't recomputed after
that check, so this assert is always trivially true. (And it has nothing to
do with if T is canonical or not.)



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@177158 91177308-0d34-0410-b5e6-96231b3b80d8