[vm/aot] Two improvements to signature shaking (reland)

- Global parameter use analysis: when a parameter is only used directly
  as arguments to other calls, only consider it used if any of the
  target parameters are used.

- A parameter can be eliminated if the TFA infers that it has a constant
  value in every implementation.

This change also extends the test of the protobuf-aware tree shaker to
run the AOT global transformations on all its test cases in order to
check that the protobuf handling in that code path is not broken by
signature shaking.

Reduces ARM64 .so size of Flutter Gallery by 0.25% uncompressed, 0.37%
with gzip and 0.45% with brotli.

Issue: #40488

TEST=Existing test suite, expectation files for TFA test, extended test
of protobuf-aware tree shaker.
Change-Id: Ib00fe362f798c92592a260f72e7bccad04246bb2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/173727
Commit-Queue: Aske Simon Christensen <[email protected]>
Reviewed-by: Martin Kustermann <[email protected]>

Author: askeksa

pkg/vm/lib/transformations/protobuf_aware_treeshaker/transformer.dart

@@ -50,6 +50,16 @@ void _treeshakeProtos(Target target, Component component, CoreTypes coreTypes,
   component.metadata.clear();
 }
 
+/// Called by the signature shaker to exclude the positional parameters of
+/// certain members whose first few parameters are depended upon by the
+/// protobuf-aware tree shaker.
+bool excludePositionalParametersFromSignatureShaking(Member member) {
+  return member.enclosingClass?.name == 'BuilderInfo' &&
+      member.enclosingLibrary.importUri ==
+          Uri.parse('package:protobuf/protobuf.dart') &&
+      _UnusedFieldMetadataPruner.fieldAddingMethods.contains(member.name.name);
+}
+
 InfoCollector removeUnusedProtoReferences(
     Component component, CoreTypes coreTypes, TransformationInfo info) {
   final protobufUri = Uri.parse('package:protobuf/protobuf.dart');