Move global objects to Runtime

Move away global constants and global namespaces out of Environment
and into a new file Runtime.

--
MOS_MIGRATED_REVID=101940218
diff --git a/src/test/java/com/google/devtools/build/lib/syntax/FunctionTest.java b/src/test/java/com/google/devtools/build/lib/syntax/FunctionTest.java
index 2b8547c..ade0bbf 100644
--- a/src/test/java/com/google/devtools/build/lib/syntax/FunctionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/syntax/FunctionTest.java
@@ -71,7 +71,7 @@
       public Object call(List<Object> args, Map<String, Object> kwargs, FuncallExpression ast,
           Environment env) throws EvalException, InterruptedException {
         params.addAll(args);
-        return Environment.NONE;
+        return Runtime.NONE;
       }
     };
     update("outer_func", outerFunc);