Merge kernel closure conversion into the Dart SDK

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

+library;
+import self as self;
+import "dart:core" as core;
+import "dart:mock" as mock;
+
+class Closure#main#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#main#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#main#function::context};
+    return #contextParameter.[](0);
+  }
+}
+static const field dynamic numbers = const <core::int>[0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
+static method main() → dynamic {
+  dynamic closures = <dynamic>[];
+  for (core::int i in self::numbers) {
+    final mock::Context #context = new mock::Context::•(1);
+    #context.parent = null;
+    #context.[]=(0, i);
+    {
+      closures.add(new self::Closure#main#function::•(#context));
+    }
+  }
+  core::int sum = 0;
+  for (core::Function f in closures) {
+    sum = sum.+(f.call());
+  }
+  core::int expectedSum = self::numbers.length.-(1).*(self::numbers.length).~/(2);
+  if(!expectedSum.==(sum)) {
+    throw core::Exception::•("Unexpected sum = ${sum} != ${expectedSum}");
+  }
+}