x/build: add tip builders with GOEXPERIMENT=aliastypeparams=1 for at least go and x/tools repo

[timothy-king]

Add a builder for >=1.24 with GOEXPERIMENT=aliastypeparams=1 for additional test coverage (#46477). aliastypeparams was introduced in 1.23. Its default is currently off. For the 1.24 release, we want to flip this to default to on.

For packages that use go/types, this also requires GODEBUG=gotypesalias=1. This includes x/tools.

We do not expect <= 1.23 to fully work with type parameterized aliases. (1.23 only supported these as a 'preview'.) The builders for #68798 (GODEBUG=gotypesalias=1) are enabled at 1.22 and 1.23. So these configurations are not expected to overlap smoothly.

[gabyhelp]

Related Issues and Documentation

• x/build: add 1.23 and tip builders with GODEBUG=gotypesalias=1 for at least the x/tools repo #68798 (closed)
• go/types, x/tools: help tool authors support the new go/types.Alias node #67263
• x/tools/gopls: handle go1.22's go/types.Alias #64581 (closed)

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[gopherbot]

Change https://go.dev/cl/609375 mentions this issue: main.star: add aliastypeparams builders

[gopherbot]

Change https://go.dev/cl/609735 mentions this issue: main.star: enable aliastypeparams builders on presubmit and postsubmit