Follow CL 41477 and add two more line position tests for yyerror calls
in the typechecker which are currently not tested.

Update #19683

Change-Id: Iacd865195a3bfba87d8c22655382af267aba47a9
Reviewed-on: https://go-review.googlesource.com/70251Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>