Misc cleanups of AST node API

- changed field names and a couple accessors to consistently use full words ("statement" instead of "stmt")

- applied several local analyzers (from IntelliJ) to remove redundant modifiers, unnecessary explicit types (yay Java 8), etc.

RELNOTES: None
PiperOrigin-RevId: 161551096
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/ValidationEnvironment.java b/src/main/java/com/google/devtools/build/lib/syntax/ValidationEnvironment.java
index bed21bc..46b4761 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/ValidationEnvironment.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/ValidationEnvironment.java
@@ -197,7 +197,7 @@
     for (Statement statement : statements) {
       if (statement instanceof FunctionDefStatement) {
         FunctionDefStatement fct = (FunctionDefStatement) statement;
-        declare(fct.getIdent().getName(), fct.getLocation());
+        declare(fct.getIdentifier().getName(), fct.getLocation());
       }
     }