pw_presubmit: Add new steps that combine tests
pw_presubmit: Add new steps that combine tests

Add gn_full_build_check and gn_full_qemu_check.

Change-Id: Ic5d0709394ee856d74f392d213af19014d32c216
Bug: 328
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/34180
Reviewed-by: Wyatt Hepler <cca3bedb37979eacd157a9bceb473582df8aea1e@google.com>
Commit-Queue: Rob Mohr <d07614a8a0b466db08f68224f87d738b0f9615cf@google.com>

google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed