Preliminary cleanup for removing Blaze-specific code from the environment

The goal is to remove parse and eval functions from Environment, as well as
isSkylark boolean.

--
MOS_MIGRATED_REVID=129202204
diff --git a/src/test/java/com/google/devtools/build/lib/syntax/SkylarkEvaluationTest.java b/src/test/java/com/google/devtools/build/lib/syntax/SkylarkEvaluationTest.java
index 4ac19c4..318bd2e 100644
--- a/src/test/java/com/google/devtools/build/lib/syntax/SkylarkEvaluationTest.java
+++ b/src/test/java/com/google/devtools/build/lib/syntax/SkylarkEvaluationTest.java
@@ -1028,7 +1028,7 @@
 
   @Test
   public void testDirFindsClassObjectFields() throws Exception {
-    new SkylarkTest().update("mock", new MockClassObject()).setUp()
+    new SkylarkTest().update("mock", new MockClassObject())
         .testExactOrder("dir(mock)", "field", "nset");
   }