Fix top-level inference errors for most of the newly failing tests.

tests/lib_strong/lib_strong.status

Index: tests/lib_strong/lib_strong.status
diff --git a/tests/lib_strong/lib_strong.status b/tests/lib_strong/lib_strong.status
index d342da7a1cd40d18f97f0bab65edcef5dc47a5e4..8ada2778b8ce706806de13688161e36e46063073 100644
--- a/tests/lib_strong/lib_strong.status
+++ b/tests/lib_strong/lib_strong.status
@@ -133,8 +133,6 @@ typed_data/float64x2_functional_test: Skip
 typed_data/int32x4_test: Skip
 
 [ $compiler == dart2analyzer && $strong ]
-convert/streamed_conversion_json_utf8_decode_test: CompileTimeError
-convert/streamed_conversion_json_utf8_encode_test: CompileTimeError
 html/custom/created_callback_test: CompileTimeError # Issue 28969
 html/custom/document_register_basic_test: CompileTimeError # Issue 28969
 html/custom/document_register_type_extensions_test: CompileTimeError # Issue 28969
@@ -143,8 +141,3 @@ html/debugger_test: CompileTimeError # Issue 28969
 html/input_element_test: CompileTimeError
 html/js_typed_interop_default_arg_test/default_value: MissingCompileTimeError # Issue 28969
 mirrors/deferred_mirrors_metadata_test: StaticWarning # Issue 28969
-mirrors/invocation_fuzz_test/emptyarray: CompileTimeError
-mirrors/invocation_fuzz_test/false: CompileTimeError
-mirrors/invocation_fuzz_test/none: CompileTimeError
-mirrors/invocation_fuzz_test/smi: CompileTimeError
-mirrors/invocation_fuzz_test/string: CompileTimeError