[dev.typeparams] test: run more tests with -G=3

This CL expands the current logic for re-running "errorcheck" tests
with -G=3 to run (almost) all regress tests that way. This exposes a
handful of additional failures, so the excluded-files list is expanded
accordingly. (The next CL addresses several of the easy test cases.)

Change-Id: Ia5ce399f225d83e817a046a3bd1a41b9681be3af
Reviewed-on: https://go-review.googlesource.com/c/go/+/320609


Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Trust: Matthew Dempsky <mdempsky@google.com>
Trust: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dan Scales <danscales@google.com>