Move foo/test/BUILD content into foo/BUILD

[jwnimmer-tri]

This is intended to be shuffle-only changes, without any novel code:

• Paste the foo/test/BUILD content at the end of foo/BUILD.
• Replace DEPS shared variable with copy-pasting into uses.
• Add test/ prefix to paths as needed.
• Use local ":libname" paths instead of "//full/paths" where possible.
• Buildifier reformatting.

Closes #4457.

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This change is 

[liangfok]

What is the motivation behind moving the contents of foo/test/BUILD into foo/BUILD? Isn't it better to keep a BUILD files closer to the files it is building? Also, per #4455, is it odd for a single BUILD file to cover code that spans a wide difference in terms its place in the overall dependency chain (tests are always last whereas foo may be far from last)?

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[jwnimmer-tri]

The motivation is that Bazel is slightly more convenient to work with when the library rules and test rules are in the same BUILD file.

The #4455 topology is about what deps = [] says, not about where BUILD files are located.

[liangfok]

Cool. Thanks!

[jwnimmer-tri]

@drake-jenkins-bot linux-gcc-bazel-experimental please

[rpoyner-tri]

+@rpoyner-tri

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Review status: 0 of 33 files reviewed at latest revision, all discussions resolved.

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Comments from Reviewable

[rpoyner-tri]

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Reviewed 33 of 33 files at r1.
Review status: all files reviewed at latest revision, all discussions resolved.

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[jwnimmer-tri]

+@david-german-tri do you want to weigh in on this (at a high level, at least)?

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Comments from Reviewable

[david-german-tri]

Only to gripe that #2182 was a suboptimal decision, and this illustrates why: we now have a mismatch between our test target paths in Bazel and the paths to the source code on the filesystem. It's not worth revisiting, though.

I've confirmed locally that the list of tests is unchanged.

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[david-german-tri]

I'm going to go ahead and merge this so that I can proceed with #4462.

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