bazel syntax: rename Runtime.NONE to Starlark.NONE and delete Runtime

...and move Runtime.NoneType to top level.

This is a breaking change to copybara.

BEGIN_PUBLIC
bazel syntax: rename Runtime.NONE to Starlark.NONE
END_PUBLIC

PiperOrigin-RevId: 280001048
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/DefaultInfo.java b/src/main/java/com/google/devtools/build/lib/analysis/DefaultInfo.java
index a168439..79e0749 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/DefaultInfo.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/DefaultInfo.java
@@ -20,8 +20,8 @@
 import com.google.devtools.build.lib.packages.NativeInfo;
 import com.google.devtools.build.lib.skylarkbuildapi.DefaultInfoApi;
 import com.google.devtools.build.lib.syntax.EvalException;
-import com.google.devtools.build.lib.syntax.Runtime;
 import com.google.devtools.build.lib.syntax.SkylarkNestedSet;
+import com.google.devtools.build.lib.syntax.Starlark;
 import javax.annotation.Nullable;
 
 /** DefaultInfo is provided by all targets implicitly and contains all standard fields. */
@@ -153,7 +153,7 @@
   }
 
   private static <T> T castNoneToNull(Class<T> clazz, Object value) {
-    if (value == Runtime.NONE) {
+    if (value == Starlark.NONE) {
       return null;
     } else {
       return clazz.cast(value);