Reapply "Collect call site information and use that for estimating parameter types"

tests/compiler/dart2js_extra/regress/4434_lib.dart

Index: tests/compiler/dart2js_extra/regress/4434_lib.dart
diff --git a/tests/language/function_getter_test.dart b/tests/compiler/dart2js_extra/regress/4434_lib.dart
similarity index 76%
copy from tests/language/function_getter_test.dart
copy to tests/compiler/dart2js_extra/regress/4434_lib.dart
index d927a045fcf7b1bb511d51e161bb1331916a2e46..2b80d99a84031006da0e449d288136787977dd17 100644
--- a/tests/language/function_getter_test.dart
+++ b/tests/compiler/dart2js_extra/regress/4434_lib.dart
@@ -2,10 +2,9 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-class A {
-  a() => 42;
-}
+#library("lib_a");
 
-main() {
-  Expect.equals(new A().a(), (new A().a)());
+class A {
+  x(A a) => a._x;
+  get _x() => null;
 }