RFR: 8146800: Reorganize logging alias code.

[Max Ockner]

Hello all,
Please review my fix which reorganizes the alias table for Unified Logging.

bug: https://bugs.openjdk.java.net/browse/JDK-8146800
webrev: http://cr.openjdk.java.net/~mockner/aliastable.03/

Summary:
How logging aliases used to handled - At the beginning of 
parse_each_vm_init_arg() in arguments.cpp, each "-XX" argument would be 
looked up in the logging alias table to see if there was a match. If a 
match was found, then the entire argument would be replaced by a 
corresponding unified logging argument. This argument would then cascade 
through the giant case structure until it was caught and handled close 
to the bottom of parse_each_vm_init_arg (which happens hundreds of lines 
later).

There is a section of code that handles aliases and deprecation for -XX 
options already. After this fix, logging aliases will be handled here 
instead of substituting entire logging expressions at the beginning of 
parse_each_vm_init_arg.

Tested with jtreg runtime tests. This includes several logging tests for 
recently aliased flags.

Thanks,
Max