RFR: 8251850: Simplify ResourceMark constructors using delegation

[Kim Barrett]

> On Aug 14, 2020, at 10:29 PM, Kim Barrett <kim.barrett at oracle.com> wrote:
> 
> Please review this simplification of the constructors for ResourceMark,
> accomplished using delegating constructors.
> 
> Also made the constructors "explicit" and the class non-copyable.
> 
> CR:
> https://bugs.openjdk.java.net/browse/JDK-8251850
> 
> Webrev:
> https://cr.openjdk.java.net/~kbarrett/8251850/open.00/
> 
> Testing:
> mach5 tier1

I should have looked further along in resourceArea.hpp. All the
changes I made to ResourceMark? DeoptResourceMark should have similar
changes made to it.

Well, I have a first round of comments from the ResourceMark changes.  I can
take those into account for DeoptResourceMark.