cmd/pkgserver: implement skipping JS tests from the DSL

cmd/pkgserver/ui/static/test.scss

@@ -13,8 +13,39 @@ details.test-node {
     > summary {
         cursor: pointer;
     }
+    &.success > summary::marker {
+        /*
+         * WebKit only supports color and font-size properties in ::marker [1],
+         * and its ::-webkit-details-marker only supports hiding the marker
+         * entirely [2], contrary to mdn's example [3]; thus, set a color as
+         * a fallback: while it may not be accessible for colorblind
+         * individuals, it's better than no indication of a test's state for
+         * anyone, as that there's no other way to include an indication in the
+         * marker on WebKit.
+         *
+         * [1]: https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/Selectors/::marker#browser_compatibility
+         * [2]: https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Elements/summary#default_style
+         * [3]: https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Elements/summary#changing_the_summarys_icon
+         */
+        color: black;
+        content: url("/static/success-closed.svg") / "success";
+    }
+    &.success[open] > summary::marker {
+        content: url("/static/success-open.svg") / "success";
+    }
     &.failure > summary::marker {
         color: red;
+        content: url("/static/failure-closed.svg") / "failure";
+    }
+    &.failure[open] > summary::marker {
+        content: url("/static/failure-open.svg") / "failure";
+    }
+    &.skip > summary::marker {
+        color: blue;
+        content: url("/static/skip-closed.svg") / "skip";
+    }
+    &.skip[open] > summary::marker {
+        content: url("/static/skip-open.svg") / "skip";
     }
 }
 
@@ -26,6 +57,10 @@ p.test-desc {
     }
 }
 
+.hidden {
+    display: none;
+}
+
 .italic {
     font-style: italic;
 }