RFR(S): 8152929: Remove UNSUPPORTED_GC_OPTION, use UNSUPPORTED_OPTION instead

[Per Liden]

Hi,

The macros UNSUPPORTED_GC_OPTION and UNSUPPORTED_OPTION do the same 
thing, but has slightly different warning messages. This patch removes 
UNSUPPORTED_GC_OPTION and uses UNSUPPORTED_OPTION instead. The 
description argument to UNSUPPORTED_OPTION was also removed to allow 
more uniform warning messages. This also meant that a couple of test 
needed adjustments.

Bug: https://bugs.openjdk.java.net/browse/JDK-8152929
Webrev: http://cr.openjdk.java.net/~pliden/8152929/webrev.0/

thanks,
Per