Support var in enhanced for loops

Fixes #463

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=308891540

Author: cushon

core/src/main/java/com/google/googlejavaformat/java/JavaInputAstVisitor.java

@@ -2561,13 +2561,21 @@ private void visitToDeclare(
       String equals,
       Optional<String> trailing) {
     sync(node);
-    TypeWithDims extractedDims = DimensionHelpers.extractDims(node.getType(), SortedDims.YES);
-    Optional<TypeWithDims> typeWithDims = Optional.of(extractedDims);
+    Optional<TypeWithDims> typeWithDims;
+    Tree type;
+    if (node.getType() != null) {
+      TypeWithDims extractedDims = DimensionHelpers.extractDims(node.getType(), SortedDims.YES);
+      typeWithDims = Optional.of(extractedDims);
+      type = extractedDims.node;
+    } else {
+      typeWithDims = Optional.empty();
+      type = null;
+    }
     declareOne(
         kind,
         annotationsDirection,
         Optional.of(node.getModifiers()),
-        extractedDims.node,
+        type,
         node.getName(),
         "",
         equals,

core/src/test/resources/com/google/googlejavaformat/java/testdata/java14.input

@@ -43,4 +43,8 @@ class Java14 {
         case WEDNESDAY              -> 9;
     };
   }
+
+  {
+    for (var arg : List.of()) {}
+  }
 }

core/src/test/resources/com/google/googlejavaformat/java/testdata/java14.output

@@ -44,4 +44,8 @@ class Java14 {
           case WEDNESDAY -> 9;
         };
   }
+
+  {
+    for (var arg : List.of()) {}
+  }
 }