Run tree shaking in strong-mode baseline tests.

pkg/kernel/testcases/strong-mode/uninitialized_fields.baseline.txt

Index: pkg/kernel/testcases/strong-mode/uninitialized_fields.baseline.txt
diff --git a/pkg/kernel/testcases/strong-mode/uninitialized_fields.baseline.txt b/pkg/kernel/testcases/strong-mode/uninitialized_fields.baseline.txt
index c4b90446c9977835fb664e6c634704b4325b130b..bef6d48d0e53c211e838b7229f80cb3fbba5884a 100644
--- a/pkg/kernel/testcases/strong-mode/uninitialized_fields.baseline.txt
+++ b/pkg/kernel/testcases/strong-mode/uninitialized_fields.baseline.txt
@@ -1,37 +1,4 @@
 library;
 import self as self;
-import "dart:core" as core;
 
-class Uninitialized extends core::Object {
-  field core::int x = null;
-  constructor •() → void
-    : super core::Object::•()
-    ;
-}
-class PartiallyInitialized extends core::Object {
-  field core::int x = null;
-  constructor •(core::int x) → void
-    : self::PartiallyInitialized::x = x, super core::Object::•()
-    ;
-  constructor noInitializer() → void
-    : super core::Object::•()
-    ;
-}
-class Initialized extends core::Object {
-  field core::int x;
-  constructor •(core::int x) → void
-    : self::Initialized::x = x, super core::Object::•()
-    ;
-}
-class Forwarding extends core::Object {
-  field core::int x;
-  constructor initialize(core::int x) → void
-    : self::Forwarding::x = x, super core::Object::•()
-    ;
-  constructor •(core::int arg) → void
-    : this self::Forwarding::initialize(arg)
-    ;
-}
-static field core::int uninitializedTopLevel = null;
-static field core::int initializedTopLevel = 4;
 static method main() → dynamic {}