Don't swallow runfiles of srcs in data runfiles of filegroup

[fmeum]

The data_runfiles of a filegroup should contain the data_runfiles of all deps in srcs, plus the data_runfiles of all deps in data. Previously, they didn't contain the former.

Related to #25329 (comment)

[fmeum]

I'm not entirely sure whether the correct behavior would be to merge in the data_runfiles or the default_runfiles of srcs as these have been deprecated for a while and Starlark rules rarely distinguish between the two. @lberki Are you able to make the call? :-)

[meteorcloudy]

Testing in downstream: https://buildkite.com/bazel/bazel-at-head-plus-downstream/builds/4493

[fmeum]

Thanks, the run looks good, all failures are caused by known issues.

[meteorcloudy]

Nice, @comius @lberki please double check this change is safe.

[lberki]

Ow. This is definitely a change that I'd love to land (DATA_RUNFILES should die) but also has a chance that it'd break things at Google. How about this: I'll kick off a test run for Google's tests tomorrow morning (Europe) (it's already too late for that today) and report back. If it comes back clean, let's submit it, if not, depending on the amount of fallout, either we'll fix it at Google or you go with the sh_library approach.

Hm?

[fmeum]

Sounds good!