RFR: 8200626: Restore history for g1ConcurrentMarkThread.*

[Erik Helin]

Hi all,

this (somewhat strange) patch restores the Mercurial (hg) history for 
the files g1ConcurrentMarkThread.{hpp, inline.hpp, cpp}. This is done by 
re-doing the commit (but make sure to `hg mv`) and then performing a 
benign merge (the merge is not part of the webrev).

I don't think the webrev will highlight that `hg mv` was properly used, 
but I have verified that
`hg log --follow src/hotspot/share/gc/g1/g1ConcurrentMarkThread.hpp` 
shows the entire history.

Bug:
https://bugs.openjdk.java.net/browse/JDK-8200626

Patch:
http://cr.openjdk.java.net/~ehelin/8200626/00/

Testing:
- hs-tier1 on Linux, macOS and Windows, all x86-64
   (mainly to ensure that everything builds correctly)

Thanks,
Erik