servo: Merge #5574 - Move unit tests to their own crates, cut time by 96% (from servo:unit-tests); r=jack

On my laptop, running `./mach test-unit` goes from about 11 minutes to 22 seconds, when run after `./mach build`.

Fix #5291.

Source-Repo: https://github.com/servo/servo
Source-Revision: 017d1053617f6769d7f355e4a97d52ae67e53d1c

servo/python/tidy.py

@@ -14,7 +14,7 @@ import fnmatch
 import itertools
 from licenseck import licenses
 
-directories_to_check = ["ports", "components"]
+directories_to_check = ["ports", "components", "tests"]
 filetypes_to_check = [".rs", ".rc", ".cpp", ".c", ".h", ".py"]
 reftest_directories = ["tests/ref"]
 reftest_filetype = ".list"
@@ -22,7 +22,7 @@ reftest_filetype = ".list"
 ignored_files = [
     # Upstream
     "support/*",
-    "tests/wpt/web-platform-tests/*",
+    "tests/wpt/*",
 
     # Generated and upstream code combined with our own. Could use cleanup
     "components/script/dom/bindings/codegen/*",