RFR: 8253433: Remove -XX:+Debugging product option

[Kim Barrett]

> On Sep 30, 2020, at 9:00 AM, Thomas Stuefe <stuefe at openjdk.java.net> wrote:
> 
> On Wed, 30 Sep 2020 12:38:30 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:
> 
>> The Debugging option shouldn't be used on the command line.  There's a SuppressErrorAt option to ignore certain
>> asserts, if there is some situation needing that. Debugging should never be used.
>> Tested with tier1 tests on 4 platforms.
> 
> src/hotspot/share/utilities/debug.cpp line 75:
> 
>> 73:
>> 74: // Set to suppress secondary error reporting.
>> 75: bool Debugging = false;
> 
> How would this work? You would set this while debugging? Does it also work in optimized coding or would the value
> getting optimized away? Maybe make volatile?

This is really just about the one existing assignment.
See the Command context class in debug.cpp.  This variable probably shouldn’t be set/reset
much of anywhere else.

> PR: https://git.openjdk.java.net/jdk/pull/434