Trivial refactoring for `PositionConfigureUtils.configureAST`
diff --git a/src/main/java/org/apache/groovy/parser/antlr4/util/PositionConfigureUtils.java b/src/main/java/org/apache/groovy/parser/antlr4/util/PositionConfigureUtils.java
index ded5a59..abd79cc 100644
--- a/src/main/java/org/apache/groovy/parser/antlr4/util/PositionConfigureUtils.java
+++ b/src/main/java/org/apache/groovy/parser/antlr4/util/PositionConfigureUtils.java
@@ -91,8 +91,6 @@
 
     public static <T extends ASTNode> T configureAST(T astNode, GroovyParser.GroovyParserRuleContext ctx, ASTNode initialStop) {
         Token start = ctx.getStart();
-        Token stop = ctx.getStop();
-
         astNode.setLineNumber(start.getLine());
         astNode.setColumnNumber(start.getCharPositionInLine() + 1);
 
@@ -100,7 +98,8 @@
             astNode.setLastLineNumber(initialStop.getLastLineNumber());
             astNode.setLastColumnNumber(initialStop.getLastColumnNumber());
         } else {
-            configureEndPosition(astNode, ctx.getStop());
+            Token stop = ctx.getStop();
+            configureEndPosition(astNode, stop);
         }
 
         return astNode;