Add mocks to flaky virtual-webgl list

Author: camdecoster

test/image/compare_pixels_collections.json

@@ -13,13 +13,29 @@
   "flaky": ["gl3d_bunny-hull"],
   "flaky_maps": ["map_density0-legend"],
   "flaky_virtual_webgl": [
+    "gl2d_parcoords_256_colors",
+    "gl2d_parcoords_coloraxis",
+    "gl2d_parcoords_constraints",
+    "gl2d_parcoords_rgba_colorscale",
+    "gl3d_cone-lighting",
     "gl3d_cone-wind",
+    "gl3d_directions-streamtube1",
+    "gl3d_directions-streamtube2",
     "gl3d_ibm-plot",
     "gl3d_isosurface_2surfaces-checker_spaceframe",
+    "gl3d_isosurface_log-axis_slices_surface-fill",
     "gl3d_isosurface_math",
+    "gl3d_isosurface_uneven-scales_ranges_iso-null",
+    "gl3d_isosurface_xycaps_volume_slices",
+    "gl3d_line-colorscale-with-markers",
     "gl3d_mesh3d_surface3d_scatter3d_line3d_error3d_log_reversed_ranges",
+    "gl3d_mesh3d_surface3d_scatter3d_orthographic",
+    "gl3d_mirror-ticks",
     "gl3d_opacity-scaling-spikes",
-    "gl3d_scatter3d-blank-text"
+    "gl3d_scatter-color-line-gradient",
+    "gl3d_scatter-color-mono-and-palette",
+    "gl3d_scatter3d-blank-text",
+    "map_predefined-styles1"
   ],
   "mathjax3": [
     "legend_mathjax_title_and_items",