Change how unresolved super sends are handled.

pkg/front_end/testcases/strong.status

 # Copyright (c) 2017, the Dart project authors. Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE.md file.
 
 # Status file for the strong_test.dart test suite. This is testing generating
 # Kernel ASTs directly, that is, code in pkg/fasta/lib/src/kernel/ with
 # strong-mode enabled.
 
 DeltaBlue: Fail
 accessors: Fail
@@ skipping 26 matching lines @@
 named_parameters: Fail
 null_aware: Fail
 operators: Fail
 optional: Fail
 platform: Fail
 prefer_baseclass: Fail
 redirecting_constructor: Fail
 redirecting_factory: Fail
 statements: Fail
 stringliteral: Fail
-super_rasta_copy: Fail
 top_level_accessors: Fail
 type_variable_as_super: Fail
 typedef: Fail
 uninitialized_fields: Fail
 unused_methods: Fail
 void-methods: Fail
 
 inference/constructors_too_many_positional_arguments: Fail # Issue #30040
 inference/downwards_inference_annotations_for_loop_variable: Fail # Issue #30035
 inference/downwards_inference_annotations_locals: Fail # Issue #30031 and Issue #30035
@@ skipping 70 matching lines @@
 rasta/issue_000067: Fail
 rasta/issue_000068: Fail
 rasta/issue_000069: Fail
 rasta/issue_000070: Fail
 rasta/issue_000080: Fail
 rasta/issue_000081: Fail
 rasta/malformed_const_constructor: Fail
 rasta/malformed_function: Fail
 rasta/malformed_function_type: Fail
 rasta/mandatory_parameter_initializer: Fail
-rasta/mixin_library: Fail
+rasta/mixin_library: RuntimeError
 rasta/native_is_illegal: Fail
 rasta/parser_error: Fail
 rasta/previsit_deferred: Fail
 rasta/static: Fail
-rasta/super: Fail
+rasta/super: RuntimeError
 rasta/super_initializer: Fail
-rasta/super_mixin: Fail
 rasta/super_operator: Fail
 rasta/supports_reflection: VerificationError
 rasta/switch_execution_case_t02: Fail
 rasta/switch_fall_through: Fail
 rasta/this_invoke: Fail
 rasta/try_label: Fail
 rasta/type_literals: Fail
 rasta/type_with_parse_error: Fail
 rasta/typedef: Fail
 rasta/unresolved: Fail
@@ skipping 14 matching lines @@
 regress/issue_29977: Crash # Issue 29977.
 regress/issue_29978: Crash # Issue 29978.
 regress/issue_29979: Crash # Issue 29979.
 regress/issue_29980: Crash # Issue 29980.
 regress/issue_29981: Crash # Issue 29981.
 regress/issue_29982: Crash # Issue 29982.
 regress/issue_29983: Crash # Issue 29983.
 regress/issue_29984: Crash # Issue 29984.
 regress/issue_29985: Crash # Issue 29985.
 regress/issue_29987: Crash # Issue 29987.