Leftover .hgtags, .hgignore

[Aleksey Shipilev]

Hi,

What is the story about leftover .hgtags and .hgignore in the repos that went through the Git 
transition? I was asking myself this about openjdk/jmh, openjdk/jcstress, openjdk/jol repos, but it 
is equally related to openjdk/jdk.

I submitted this for openjdk/jdk, and can RFR the removal:
   https://bugs.openjdk.java.net/browse/JDK-8254178

Thoughts?

-- 
Thanks,
-Aleksey