Move compile fail tests

[BD103]

Objective

• Follow-up of Add README.md to all crates #13184 :)
• We use ui_test to test compiler errors for our custom macros.
• There are four crates related to compile fail tests
  • bevy_ecs_compile_fail_tests, bevy_macros_compile_fail_tests, and bevy_reflect_compile_fail_tests, which actually test the macros.
  • bevy_compile_test_utils, which provides helpers and common patterns for these tests.
• All of these crates reside within the crates directory.
• This can be confusing, especially for newcomers. All of the other folders in crates are actual published libraries, except for these 4.

Solution

• Move all compile fail tests to a compile_fail folder under their corresponding crate.
  • E.g. crates/bevy_ecs_compile_fail_tests would be moved to crates/bevy_ecs/compile_fail.
• Move bevy_compile_test_utils to tools/compile_fail_utils.

There are a few benefits to this approach:

1. An internal testing detail is less intrusive (and confusing) for those who just want to browse the public Bevy interface.
2. Follows a pre-existing approach of organizing related crates inside a larger crate's folder.
   • See bevy_gizmos/macros for an example.
3. Makes consistent the terms compile_test, compile_fail, and compile_fail_test in code. It's all just compile_fail now, because we are specifically testing the error messages on compiler failures.
   • To be clear it can still be referred to by these terms in comments and speech, just the names of the crates and the CI command are now consistent.

Testing

Run the compile fail CI command:

cargo run -p ci -- compile-fail

If it still passes, then my refactor was successful.

[BD103]

cc @Brezak, who previously worked on migrating our compile fail tests to ui_test in #12810.

[BD103]

The files changed (105) may be intimidating, but it's not actually that bad. The actual lines changed are just , the rest are just moved, unmodified files.

[Brezak]

Looks ok. The documentation just needs to be fixed

[alice-i-cecile]

I agree with the changes here: these are way less confusing if they're not top-level crates.

Once the links are fixed this LGTM.

[soqb]

LGTM.

side note: i feel like we shouldn't put compile-succeed tests in these crates, since its much easier iteratively to drop them into regular #[test]s, since these tests are still flaky outside of ci.