Change how unresolved super sends are handled.

pkg/front_end/testcases/strong.status

Index: pkg/front_end/testcases/strong.status
diff --git a/pkg/front_end/testcases/strong.status b/pkg/front_end/testcases/strong.status
index 15859948ef0871194d4449f5d3c2660abbf2a47e..7d6118f74734328141cf7acc672feb53a77df9cc 100644
--- a/pkg/front_end/testcases/strong.status
+++ b/pkg/front_end/testcases/strong.status
@@ -44,7 +44,6 @@ 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
@@ -135,14 +134,13 @@ 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