A bad HG merge in the two test files led to several valid tests being @Ignore'd in those files:

modules/web/src/test/java/com/sun/webkit/SharedBufferTest.java
modules/web/src/test/java/com/sun/webkit/SimpleSharedBufferInputStreamTest.java

The bad merge changeset was:

http://hg.openjdk.java.net/openjfx/8u-dev/rt/rev/f4a5488364ea

changeset: 10042:f4a5488364ea
parent: 10007:24bcf0fd597a
parent: 10041:cd83202021ac
user: kcr
date: Thu Jan 25 09:20:56 2018 -0800
summary: Merge

The @Ignore annotations in question were added to tests that were later removed in another branch, During the resolution of the merge conflicts, the lines with "@Test @Ignore" were mistakenly taken, even though those tests were removed. This had the net effect of skipping (@Ignor'ing) each test method that happened to be next to a removed method.

The solution is to remove all @Ignore statements from those two files to correct this mistake and allow those tests to be run.