Merge kernel closure conversion into the Dart SDK

pkg/kernel/testcases/closures/capture_this.dart.expect

+library;
+import self as self;
+import "dart:core" as core;
+import "dart:mock" as mock;
+
+class C extends core::Object {
+  field dynamic x = null;
+  constructor •() → void
+    : super core::Object::•()
+    ;
+  method m() → dynamic {
+    final mock::Context #context = new mock::Context::•(1);
+    #context.parent = null;
+    #context.[]=(0, this);
+    return new self::Closure#C#m#function::•(#context);
+  }
+  method f() → dynamic {
+    final mock::Context #context = new mock::Context::•(1);
+    #context.parent = null;
+    #context.[]=(0, this);
+    return new self::Closure#C#f#function::•(#context);
+  }
+}
+class Closure#C#m#function extends core::Object implements core::Function {
+  field core::String note = "This is temporary. The VM doesn't need closure classes.";
+  field mock::Context context;
+  constructor •(final mock::Context context) → dynamic
+    : self::Closure#C#m#function::context = context
+    ;
+  method call(dynamic v) → dynamic {
+    "This is a temporary solution. In the VM, this will become an additional parameter.";
+    final mock::Context #contextParameter = this.{self::Closure#C#m#function::context};
+    return #contextParameter.[](0).x = v;
+  }
+}
+class Closure#C#f#function#function extends core::Object implements core::Function {
+  field core::String note = "This is temporary. The VM doesn't need closure classes.";
+  field mock::Context context;
+  constructor •(final mock::Context context) → dynamic
+    : self::Closure#C#f#function#function::context = context
+    ;
+  method call() → dynamic {
+    "This is a temporary solution. In the VM, this will become an additional parameter.";
+    final mock::Context #contextParameter = this.{self::Closure#C#f#function#function::context};
+    return #contextParameter.[](0).x;
+  }
+}
+class Closure#C#f#function extends core::Object implements core::Function {
+  field core::String note = "This is temporary. The VM doesn't need closure classes.";
+  field mock::Context context;
+  constructor •(final mock::Context context) → dynamic
+    : self::Closure#C#f#function::context = context
+    ;
+  method call() → dynamic {
+    "This is a temporary solution. In the VM, this will become an additional parameter.";
+    final mock::Context #contextParameter = this.{self::Closure#C#f#function::context};
+    return new self::Closure#C#f#function#function::•(#contextParameter);
+  }
+}
+static method main() → dynamic {
+  self::C c = new self::C::•();
+  c.x = 41;
+  c.m().call(42);
+  if(!42.==(c.x))
+    throw "Unexpected value in c.x: ${c.x}";
+  dynamic result = c.f().call().call();
+  if(!42.==(result))
+    throw "Unexpected value from c.f()()(): ${result}";
+}