RFR [XXS]: 8242000: clean up list of environment variables printed in hs_err file

[Baesken, Matthias]

Hello, please review this very small cleanup change.

When discussing the environment variables printed in the hs_err file, we found that
some cleanup should be done , David  pointed out  :

>> I think we can dispense with LD_ASSUME_KERNEL, and _JAVA_SR_SIGNUM is
>> used on Linux, BSD and AIX. :) Not for this change of course.


Bug/webrev :
https://bugs.openjdk.java.net/browse/JDK-8242000

http://cr.openjdk.java.net/~mbaesken/webrevs/8242000.0/

Thanks, Matthias