[dart2wasm] Fix runtime type tests

This was originally implemented in a289c4d but then reverted in dc33261
as it broke Flutter: https://github.com/flutter/flutter/issues/124282.

The problematic code in Flutter was updated, so landing the fix again.

Original commit message:

`emitTypeTest` optimizes a test like `x is List<T>` where `x :
Iterable<T>`, i.e. tested-against type is a subtype of the operand's
static type. In these cases we can check just the class ID of the
operand without checking the type arguments.

However this optimization cannot be done when the types don't have same
number of type arguments. Example:

    class H1<T> {}

    bool test(Object o) {
      return o is H1<num>;
    }

    void main() {
      print(test(H1<Object>()));
    }

Here `H1<num> <: Object`, but we still need to check the type parameter.

This CL checks that the types have the same number of type arguments
before optimizing the test.

Fixes #51187.

This fix reveals another bug in `static_interop_test`, which is tracked
in #51200. The test is updated to work around the bug for now.

New passing tests:

- co19/LanguageFeatures/Patterns/matching_cast_A01_t01
- co19/LanguageFeatures/Patterns/matching_list_A01_t01
- co19/LanguageFeatures/Patterns/matching_list_A01_t02
- co19/LanguageFeatures/Patterns/matching_list_A01_t03
- co19/LanguageFeatures/Patterns/matching_map_A01_t01
- co19/LanguageFeatures/Patterns/matching_map_A01_t02
- co19/LanguageFeatures/Patterns/matching_object_A01_t01
- co19/LanguageFeatures/Patterns/matching_object_A01_t02
- co19/LanguageFeatures/Patterns/record_A01_t03
- co19/LanguageFeatures/Patterns/record_A01_t06
- co19/LanguageFeatures/Patterns/record_A01_t07
- co19/LanguageFeatures/Patterns/record_A01_t08
- co19/LanguageFeatures/Patterns/record_A01_t09
- language/generic/deep_test
- language/generic_methods/type_expression_test
- language/patterns/object_pattern_inference_test

Change-Id: Ia08ef466f74c3c55a61d4dbf0088e4b43713ee1d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/307046
Commit-Queue: Ömer Ağacan <omersa@google.com>
Reviewed-by: Joshua Litt <joshualitt@google.com>

pkg/dart2wasm/lib/types.dart

@@ -611,16 +611,23 @@ class Types {
     }
 
     if (type.typeArguments.any((t) => t is! DynamicType)) {
-      // If the tested-against type as an instance of the static operand type
-      // has the same type arguments as the static operand type, it is not
-      // necessary to test the type arguments.
+      // Type has at least one type argument that is not `dynamic`.
+      //
+      // In cases like `x is List<T>` where `x : Iterable<T>` (tested-against
+      // type is a subtype of the operand's static type and the types have same
+      // number of type arguments), it is not necessary to test the type
+      // arguments.
       Class cls = translator.classForType(operandType);
       InterfaceType? base = translator.hierarchy
           .getTypeAsInstanceOf(type, cls,
               isNonNullableByDefault:
                   codeGen.member.enclosingLibrary.isNonNullableByDefault)
           ?.withDeclaredNullability(operandType.declaredNullability);
-      if (base != operandType) {
+
+      final sameNumTypeParams = operandType is InterfaceType &&
+          operandType.typeArguments.length == type.typeArguments.length;
+
+      if (!(sameNumTypeParams && base == operandType)) {
         makeType(codeGen, type);
         codeGen.call(translator.isSubtype.reference);
         _endPotentiallyNullableBlock();

tests/web/wasm/static_interop_test.dart

@@ -311,7 +311,7 @@ extension AnonymousJSClassExtension on AnonymousJSClass {
   external String? get bleep;
   external int? get goo;
   external int? get ooo;
-  external List<double>? saz;
+  external List<Object?>? saz;
   external List<double>? zoo;
 }