Skylark: Remove static type checking of variables/functions.

There are still some static checks (check existence of variable/function,
readonly variables, etc.). More cleanup will come later.

--
MOS_MIGRATED_REVID=90979748
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/FunctionDefStatement.java b/src/main/java/com/google/devtools/build/lib/syntax/FunctionDefStatement.java
index 5b0119e..56ad4b6 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/FunctionDefStatement.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/FunctionDefStatement.java
@@ -117,7 +117,7 @@
           }
         }
       }
-      localEnv.update(name, argType, getLocation());
+      localEnv.declare(name, getLocation());
     }
     for (Statement stmts : statements) {
       stmts.validate(localEnv);