Remove an overly-eager assertion when replacing tokens with an

annotation token, because some of the tokens we're annotating might
not be in the set of cached tokens (we could have consumed them
unconditionally).

Also, move the tentative parsing from ParseTemplateTemplateArgument
into the one caller that needs it, improving recovery.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@86904 91177308-0d34-0410-b5e6-96231b3b80d8