Add data-disabled to test fixtures (#1286)

Summary:
Pull Request resolved: https://github.com/facebook/yoga/pull/1286

This can be marked in fixtures to skip a test without commenting it out. We add one more usage of this.

The same functionality existed (unused) before for `experiments`, which I changed to `data-experiments`.

Formatting of JS tests changed to be closer to what Prettier would output, and to remove usage of `Yoga.UNDEFINED` which doesn't existi and just resolves to `undefined` (this is converted to NaN by the wrapper layer).

Reviewed By: yungsters

Differential Revision: D45723003

fbshipit-source-id: 337af319ab1c1c12047d6579da8c7e63b4f1537a

java/tests/com/facebook/yoga/YGFlexDirectionTest.java

@@ -11,6 +11,7 @@ package com.facebook.yoga;
 
 import static org.junit.Assert.assertEquals;
 
+import org.junit.Ignore;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.Parameterized;