runtime: adjust tests for gofrontend

- don't run tests that depend on SetCgoTraceback
- don't expect a '(' after the function name in a traceback
- change the expected name of nested functions in a traceback

These tests are not currently run, but they will be soon.

Change-Id: Ia898ce5cf0ff8595fac09b223db832f5f5c25118
Reviewed-on: https://go-review.googlesource.com/46453
Reviewed-by: Than McIntosh <thanm@google.com>
3 files changed