SuperSize: Don't join dex method classes in (No path)

Change-Id: I027ecd4022ca78872c32188e22c997826bf60027
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1917240Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Jasper Chapman-Black <jaspercb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#715286}

tools/binary_size/libsupersize/static/tree-worker.js

@@ -224,7 +224,8 @@ class TreeBuilder {
     const isFileNode = node.type[0] === _CONTAINER_TYPES.FILE;
     const hasDex = node.childStats[_DEX_SYMBOL_TYPE] ||
         node.childStats[_DEX_METHOD_SYMBOL_TYPE];
-    if (!isFileNode || !hasDex || !node.children) return node;
+    const isNoPath = node.idPath === "";
+    if (!isFileNode || !hasDex || isNoPath || !node.children) return node;
 
     /** @type {Map<string, TreeNode>} */
     const javaClassContainers = new Map();