[skqp] More args for skqp related scripts

- allows to choose api versions in run_testlab.go
- adds api_version and work_arounds to generate_gn_args

Bug: skia:
Change-Id: I87516b493f4d8eef3689d1722a5dd864131a44f8
Reviewed-on: https://skia-review.googlesource.com/102900
Reviewed-by: Derek Sollenberger <djsollen@google.com>
Reviewed-by: Ben Wagner <benjaminwagner@google.com>
Commit-Queue: Stephan Altmueller <stephana@google.com>
3 files changed