RFR: 8245723: Remove PrintCompressedOopsMode and gc+heap+coops info log to debug level

[stefan.johansson at oracle.com]

Hi,

Please review this change that removes the deprecated diagnostic option 
PrintCompressedOopsMode.

Webrev: http://cr.openjdk.java.net/~sjohanss/8245723/00/
JBS: https://bugs.openjdk.java.net/browse/JDK-8245723

Summary
After adding the new gc+init logging in JDK-8244817, the info logging on 
gc+heap+coops can be moved to debug level. When looking into this I 
realized that gc+heap+coops=info has an old alias flag, 
PrintCompressedOopsMode, connected to it. I see no reason keeping this 
flag around and from what I understand we don't need to do anything 
special since it has been deprecated since JDK 9.

Testing
Locally verified output and run the tests affected. Also Mach5 tier1-2.

Thanks,
Stefan