RFR: Fix various formattings and namings in shared GC code

[Aleksey Shipilev]

On 11/28/18 11:27 AM, Roman Kennke wrote:
> Based on Kim's review [1], this fixes a number for formattings and
> namings in shared GC code.
> 
> http://cr.openjdk.java.net/~rkennke/fix-gc-formattings-namings/webrev.00/

Looks good to me.

-Aleksey