RFR: 8253270: Limit fastdebug inlining in G1 evacuation

[Kim Barrett]

> On Sep 17, 2020, at 5:45 AM, Albert Mingkun Yang <ayang at openjdk.java.net> wrote:
>> It also speeds up compilation of that file in fastdebug builds by a noticeable amount.
> 
> I see; I believe this is worth mentioning in the comments; sth like these functions should be inlined for performance
> reasons in release build, and should *not* be inlined for faster-build reasons in debug build. IOW, this new macro is
> not only a workaround for compiler bugs but a deliberate choice for certain purposes, which justifies its long-term
> presence.

Done.