RFR (S) 8196199: Remove miscellaneous oop comparison operators

[Kim Barrett]

> On Jan 31, 2018, at 4:05 PM, coleen.phillimore at oracle.com wrote:
> 
> 
> 
> On 1/31/18 4:01 PM, Kim Barrett wrote:
>>> On Jan 31, 2018, at 2:30 PM, harold seigel <harold.seigel at oracle.com> wrote:
>>> 
>>> Hi Coleen,
>>> 
>>> This change looks good.
>>> 
>>> In jniCheck.cpp, you could use the is_null(oop obj) function defined in oop.hpp instead of 'oop == NULL’.
>> I like this suggestion, and wish I’d thought of it while writing the initial code.  I think it should be applied to all of the former uses of operator!.  Coleen?
> 
> There are a zillion places where oop is compared with NULL.

I wasn’t suggesting a zillion places be changed.  Only the half dozen places that formerly used operator! (via “!x”)
and are being changed to instead use “x == NULL” in 8196199.01/webrev.