[C#] Stabilize tests (microsoft#551)

* Seeing Out of Memory failures on Release \ Any CPU test runs. These are caused by log allocation sizes being too big. I reduced several tests to try to stabilize the tests in all configs.

* Stabilized a few tests that were sporadically failing on Release Any CPU config. Getting out of memory errors so reduced the size of the KV Log.

* RecoveryTestByAllocatorType was failing on Debug x64 due to the log size was not valid. So putting size back to what it was

* Change Assert.IsTrue -> Assert.AreEqual (and other more-precise calls). Remove Console.WriteLine in tests and replace with Debug.WriteLine in LocalMemoryDevice. Fix RecoverTests Segment and Page SizeBits to match reduced LMD capacity argument

* Restore RecoveryTests Segment and Page SizeBits per Darren's push

* Updated a couple Device Faster Log Tests to use "using var" to make sure device and logs are cleaned up properly when the test is done.

Co-authored-by: TedHartMS <15467143+TedHartMS@users.noreply.github.com>
Co-authored-by: Badrish Chandramouli <badrishc@microsoft.com>

[C++] Fix epoch scan range (microsoft#484)

* [C++] Fix epoch scan range

* updates

* fix testcase

[C#] Fixes and refactoring of FASTERAsync (microsoft#480)

* Fix to move await of flushtask to Slow*Async

* Fix setting of RecordInfo in ReadAsync

* FASTERAsync: do not use CompleteAsync.GetAwaiter() in Complete()

* fix asyncOp and asyncOperation usage

* Add XML comment for throttleLimit param

* Change flushTask to a SemaphoreSlim to avoid GetAwaiter().GetResult() in the sync case

* Add AsyncPool.Get() for sync paths and change MLSD to use it instead of GetAwaiter().GetResult()

* Add ConfigureAwait(false) to all awaits

* Break FASTERAsync out to separate files

* Prep for RMW refactor

* Rename UpdelAsync -> UpdateAsync

* Refactor RMWAsync to use UpdateAsync

* Add GetAwaiter().GetResult in one void-returning function where it can't be avoided,

* Update AsyncStress to include options for rmw-only, upsert-only, large vs. small memory log, and whether to use Value, Reference, or Span data types

* Remove obsolete RecordAccessor.cs

* Make IHeapContainer implement IDisposable

* Fix the TakeFullCheckpoint overload without CheckpointType to call through to the overload with it

* Update session.XxxAsync() doc comments for clarity and to emphasize the need to complete operations to avoid leaks

* add raw stddev %s to output

* Add -NoLock option to compare_runs

* Add comments to IUpdateAsyncOperation; fix comment on ccompare_runs

Co-authored-by: TedHartMS <15467143+TedHartMS@users.noreply.github.com>

Merge branch 'master' of https://github.com/microsoft/FASTER

Update 20-fasterkv-basics.md

[C#] remote update to latest IFunctions

[C#] minor cleanup

[C#] Support concurrent device dispose and async commit (microsoft#423)

[C#] Dispose input on pending context dispose. (microsoft#414)

Fix and re-enable RecordInfoLockTest; remove no-longer-needed re-entr…

…ancy from RecordInfo.SpinLock() (microsoft#409)