Move kernel baseline tests to front_end.

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

Index: pkg/kernel/testcases/strong-mode/null_aware.baseline.txt
diff --git a/pkg/kernel/testcases/strong-mode/null_aware.baseline.txt b/pkg/kernel/testcases/strong-mode/null_aware.baseline.txt
deleted file mode 100644
index 7788c083b1827f0bc344a9c1e58dfe645a8d444b..0000000000000000000000000000000000000000
--- a/pkg/kernel/testcases/strong-mode/null_aware.baseline.txt
+++ /dev/null
@@ -1,22 +0,0 @@
-library;
-import self as self;
-import "dart:core" as core;
-
-class Foo extends core::Object {
-  field core::int field = null;
-  static field core::int staticField = null;
-  constructor •() → void
-    : super core::Object::•()
-    ;
-}
-static method main() → dynamic {
-  self::Foo foo = new self::Foo::•();
-  let final self::Foo #t1 = foo in #t1.==(null) ? null : #t1.{self::Foo::field} = 5;
-  self::Foo::staticField = 5;
-  let final self::Foo #t2 = foo in #t2.{self::Foo::field}.==(null) ? #t2.{self::Foo::field} = 5 : null;
-  self::Foo::staticField.==(null) ? self::Foo::staticField = 5 : null;
-  let final self::Foo #t3 = foo in #t3.==(null) ? null : #t3.{self::Foo::field}.==(null) ? #t3.{self::Foo::field} = 5 : null;
-  self::Foo::staticField.==(null) ? self::Foo::staticField = 5 : null;
-  core::int intValue = let final core::int #t4 = foo.{self::Foo::field} in #t4.==(null) ? 6 : #t4;
-  core::num numValue = let final core::int #t5 = foo.{self::Foo::field} in #t5.==(null) ? 4.5 : #t5;
-}