dev: create an alias for buildtest

[knz]

The buildtest command, available via the Makefile, is useful to complement build (or buildshort) to verify that all the code in go packages can be compiled without errors.

We want this target to check the build process, but without the overhead of actually running the test.

Ricky has explained in this comment that we can obtain this with the following command:

bazel query 'kind(go_test, pkg/whatever/...)' | xargs dev build

However this is cumbersome to type and hard to remember.

Instead, the dev command should contain a shorthand alias for it.

cc @rickystewart @irfansharif

Jira issue: CRDB-12091

[irfansharif]

Haven't investigated, but there's also https://docs.bazel.build/versions/main/command-line-reference.html#flag--build_tests_only that might be relevant.

[irfansharif]

dev build tests is now a thing.