Add virtual tests for XHR with mojo-loading

third_party/WebKit/LayoutTests/VirtualTestSuites

 [
   {
     "prefix": "gpu",
     "base": "fast/canvas",
     "args": ["--enable-accelerated-2d-canvas",
              "--disable-display-list-2d-canvas"]
   },
   {
     "prefix": "display_list_2d_canvas",
     "base": "fast/canvas",
@@ skipping 268 matching lines @@
     "base": "fast/parser",
     "args": ["--disable-blink-features=ParseHTMLOnMainThread", "--blink-settings=parseHTMLOnMainThreadCoalesceChunks=true"]
   },
   {
     "prefix": "mojo-loading",
     "base": "webexposed",
     "args": ["--enable-blink-features=LoadingWithMojo"]
   },
   {
     "prefix": "mojo-loading",
-    "base": "http/tests/xmlhttprequest/web-apps",
+    "base": "http/tests/xmlhttprequest",
     "args": ["--enable-blink-features=LoadingWithMojo"]
   },
   {
     "prefix": "scalefactor150",
     "base": "fast/events/synthetic-events",
     "args": ["--force-device-scale-factor=1.5"]
   },
   {
     "prefix": "enable_wasm",
     "base": "http/tests/wasm",
@@ skipping 18 matching lines @@
     "prefix": "layout_ng",
     "base": "fast/block/margin-collapse",
     "args": ["--enable-blink-features=LayoutNG"]
   },
   {
     "prefix": "layout_ng",
     "base": "fast/block/float",
     "args": ["--enable-blink-features=LayoutNG"]
   }
 ]