Move kernel baseline tests to front_end.

pkg/kernel/testcases/input/escape.dart

Index: pkg/kernel/testcases/input/escape.dart
diff --git a/pkg/kernel/testcases/input/escape.dart b/pkg/kernel/testcases/input/escape.dart
deleted file mode 100644
index ba58d2a92d71da1d8c02a76f4a77e2186690ee90..0000000000000000000000000000000000000000
--- a/pkg/kernel/testcases/input/escape.dart
+++ /dev/null
@@ -1,44 +0,0 @@
-class A {
-  var field;
-}
-
-class B {
-  var field;
-}
-
-class C {
-  operator ==(x) => false;
-}
-
-class X implements A, B {
-  var field;
-}
-
-void useAsA(A object) {
-  var _ = object.field;
-}
-
-void useAsB(B object) {
-  var _ = object.field;
-  escape(object);
-}
-
-void escape(x) {
-  x ??= "";
-  x ??= 45;
-  if (x is! int && x is! String) {
-    x.field = 45;
-  }
-}
-
-main() {
-  // escape("");
-  // escape(45);
-
-  var object = new X();
-  useAsA(new A());
-  useAsA(object);
-
-  useAsB(new B());
-  useAsB(object);
-}