Move kernel baseline tests to front_end.

pkg/front_end/test/fasta/rasta/super_operator.dart.dartk.expect

-library;
-import self as self;
-import "dart:core" as core;
-
-class A extends core::Object {
-  constructor •() → self::A
-    : super core::Object::•();
-  operator +(core::String s) → dynamic
-    return null;
-  operator [](dynamic i) → dynamic
-    return null;
-  operator []=(dynamic i, dynamic val) → dynamic {}
-}
-class B extends self::A {
-  constructor •() → self::B
-    : super self::A::•();
-  operator +(core::String s) → dynamic
-    return super.{self::A::+}("${s}${s}");
-  operator [](dynamic i) → dynamic
-    return super.{self::A::[]}(i);
-  operator []=(dynamic i, dynamic val) → dynamic
-    return let final dynamic #t1 = let final dynamic #t2 = i in let final dynamic #t3 = i = #t2.+(1) in #t2 in let final dynamic #t4 = super.{self::A::[]}(#t1).+(val) in let final dynamic #t5 = super.{self::A::[]=}(#t1, #t4) in #t4;
-}
-class Autobianchi extends core::Object {
-  constructor •() → self::Autobianchi
-    : super core::Object::•();
-  method g() → dynamic
-    return super.[](0);
-}