[record_use] Only record definitions with a package: uri

Record only for definitions in libraries with a `package:` uri.

* Converts all the tests to be in packages.
  * Bonus: This removes the uri-mapping in equality checks.
  * These packages are added to the root pub workspace.
  * For the dart2js tests we need to do some juggling to keep the
    tests files in memory.
* Only support `package:` uris
  * Removed all the `relativizeUri` code for file paths.
  * Start emitting errors on non `package:` uris with a `@RecordUse()`
    annotation.

Unrelated cleanups:

* We no longer support recording const instances in annotations, this
  PR cleans up code in `kernel` and `type_flow`.

TEST=pkg/compiler/test/record_use/record_use_test.dart
TEST=pkg/dart2wasm/test/record_use_test.dart
TEST=pkg/vm/test/transformations/record_use_test.dart

Closes: https://github.com/dart-lang/native/issues/2891
Change-Id: I1bc6905291230375e185930d2c000700ac778f85
Cq-Include-Trybots: luci.dart.try:dart2wasm-asserts-linux-chrome-try,dart2wasm-asserts-minified-linux-d8-try,dart2wasm-linux-chrome-try,dart2wasm-linux-d8-try,dart2wasm-linux-firefox-try,dart2wasm-linux-jscm-chrome-try,dart2wasm-linux-optimized-jsc-try,pkg-linux-debug-try,pkg-linux-release-arm64-try,pkg-linux-release-try,pkg-mac-release-arm64-try,pkg-mac-release-try,pkg-win-release-arm64-try,pkg-win-release-try,dart2js-canary-linux-try,dart2js-hostasserts-linux-d8-try,dart2js-linux-chrome-try,dart2js-linux-firefox-try,dart2js-mac-chrome-try,dart2js-mac-safari-try,dart2js-minified-csp-linux-chrome-try,dart2js-minified-linux-d8-try,dart2js-unit-linux-x64-release-try,dart2js-win-chrome-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/478920
Reviewed-by: Nate Biggs <natebiggs@google.com>
Commit-Queue: Daco Harkes <dacoharkes@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>

pubspec.yaml

@@ -28,6 +28,7 @@ workspace:
   - pkg/build_integration
   - pkg/cfg
   - pkg/compiler
+  - pkg/compiler/test/record_use/data
   - pkg/dart2bytecode
   - pkg/dart2js_info
   - pkg/dart2js_runtime_metrics
@@ -75,6 +76,7 @@ workspace:
   - pkg/testing
   - pkg/test_runner
   - pkg/vm
+  - pkg/vm/testcases/transformations/record_use
   - pkg/vm_service
   - pkg/vm_service_interface
   - pkg/vm_service_protos