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/main/java/com/google/devtools/build/lib/rules/SkylarkRuleClassFunctions.java b/src/main/java/com/google/devtools/build/lib/rules/SkylarkRuleClassFunctions.java
index 1ca229c..4c070b4 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/SkylarkRuleClassFunctions.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/SkylarkRuleClassFunctions.java
@@ -68,6 +68,7 @@
 import com.google.devtools.build.lib.syntax.FuncallExpression;
 import com.google.devtools.build.lib.syntax.FunctionSignature;
 import com.google.devtools.build.lib.syntax.Label;
+import com.google.devtools.build.lib.syntax.Runtime;
 import com.google.devtools.build.lib.syntax.SkylarkCallbackFunction;
 import com.google.devtools.build.lib.syntax.SkylarkEnvironment;
 import com.google.devtools.build.lib.syntax.SkylarkList;
@@ -250,7 +251,7 @@
         // We'll set the name later, pass the empty string for now.
         RuleClass.Builder builder = new RuleClass.Builder("", type, true, parent);
 
-        if (attrs != Environment.NONE) {
+        if (attrs != Runtime.NONE) {
           for (Map.Entry<String, Attribute.Builder> attr : castMap(
               attrs, String.class, Attribute.Builder.class, "attrs").entrySet()) {
             Attribute.Builder<?> attrBuilder = (Attribute.Builder<?>) attr.getValue();
@@ -267,7 +268,7 @@
           builder.setOutputsDefaultExecutable();
         }
 
-        if (implicitOutputs != Environment.NONE) {
+        if (implicitOutputs != Runtime.NONE) {
           if (implicitOutputs instanceof BaseFunction) {
             BaseFunction func = (BaseFunction) implicitOutputs;
             final SkylarkCallbackFunction callback =