For correct platform name in TH, the buildername must contain the pgo
string in the buildername. We work a bit more generic by matching any
build variant.
This makes heavy use of by-test-platform to distinguish the various platforms, since Android
mozharness invocations differ substantially from desktop.
MozReview-Commit-ID: GsZFij6VPTf
This combines all of the transforms into a single file, `tests.py`.
It's not quite copy/paste: the transforms have been combined in several cases.
The generated taskgraph does not change with this commit, though.
MozReview-Commit-ID: HA02M8V0SsG