Fix GLES wireframe overlay with non-indexed draw

Wireframe overlay was missing the offset of the first vertex in the
draw call and resulted in showing an incorrect wireframe.

This is easily fixed by using the vertexOffset as the first index to
use, just like an indexOffset.

renderdoc/driver/gl/gl_overlay.cpp

@@ -805,9 +805,10 @@ ResourceId GLReplay::RenderOverlay(ResourceId texid, FloatVector clearCol, Debug
       {
         // generate 'index' list
         rdcarray<uint32_t> idxs;
+        uint32_t offset = action->vertexOffset;
         idxs.resize(action->numIndices);
         for(uint32_t i = 0; i < action->numIndices; i++)
-          idxs[i] = i;
+          idxs[i] = i + offset;
         PatchLineStripIndexBuffer(action, drawParams.topo, NULL, NULL, idxs.data(), patchedIndices);
       }