internal: adapt to testing.TB.Context in Go 1.24
Thanks to Roger's proposal at https://go.dev/issue/36532,
Go at master just gained a new method in the testing package:
pkg testing, type TB interface, Context() context.Context
Our cuetdtest.M and cuetxtar.Test types implement testing.TB
as of Go 1.23, but with the addition of this new method,
our own `Context() cue.Context` methods conflict with the above.
Rename our Context methods to CueContext, which resolves this conflict
and is likely less confusing in the context of a testing.TB anyway.
Add testing.TB interface implementation assertions in both packages.
This way, the next time Go's testing.TB interface grows,
the errors will directly point to these two packages as build errors
as opposed to pointing to the dozen of downstream test packages.
Signed-off-by: Daniel Martí <mvdan@mvdan.cc>
Change-Id: I51869b22f42209e133056adca35a6970e47facc9
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1199833
Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com>
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>
Reviewed-by: Matthew Sackman <matthew@cue.works>