This commit backports #3021, a default implementation of the
`contextView()` method of the FluxSink, MonoSink and SynchronousSink
"old sinks" classes.

The backport is necessary because the new method was not added only in
3.5.0-M1 as initially stated, but in 3.4.17 as well.

Backport of commit 6eecf85.
See #2971, #2974 and #3021.

The EmitterProcessor#remove method causes retaining of subscribers if
the removal is done in parallel, as the CAS failure doesn't cause a
new loop iteration.

This applies to direct instantiations of EmitterProcessor as well as
Sinks.many().onBackpressureBuffer sinks.

This commit fixes the method to loop back when the CAS fails.

Fixes #3028.

This commit contains the following upgrades:
 - action Checkout to `7884fca` ie. v2.4.2 (supersedes and closes #3020)
 - test dependency Mockito to v4.5.1 (supersedes and closes #3022)
 - plugin Spotless to v6.5.0 (supersedes and closes #3000)
 - plugin Artifactory to v4.28.2 (supersedes and closes #3027)

This commit logs the class name of the mapper provided to FluxMap,
FluxMapFuseable and FluxMapSignal operators in the 

NB: The later is exposed in the API as `flatMap(Function,Function,Function)`.

Fixes #2982.

Co-authored-by: Simon Baslé <sbasle@vmware.com>

This commit upgrades the following dependencies:
 - plugin download to v5.1.0 (supersedes and fixes #3018)
 - plugin gradleEnterprise to v3.10 (supersedes and fixes #3023)
 - plugin spotless to v6.5.2 (supersedes and fixes #3032)
 - dependency byteBuddy to v1.12.10 (supersedes and fixes #3033)