[2019-12] Bump msbuild to track mono-2019-12 (mono#19662)

* [2019-12] Bump msbuild to track mono-2019-12

* [2019-12] Bump msbuild to track mono-2019-12

* [2019-12] Bump msbuild to track mono-2019-12

[2019-12] Bump msbuild to track mono-2019-12 (mono#19622)

* [2019-12] Bump msbuild to track mono-2019-12

* Bump nuget.exe to 5.6.0-preview2

* Bump roslyn to 3.6.0-4.20222.3 to match msbuild

[mono-2019-12] Bump corefx to get mono/corefx#396 (mono#19428)

Co-authored-by: Mitchell Hwang <[email protected]>

[2019-12] [merp] Add breadcrumb for StackHash (mono#19243)

* [merp] Add breadcrumb for StackHash

Contributes to mono#18715

Co-authored-by: Alexis Christoforides <[email protected]>

[2019-12] [corlib] Capture the ExceptionDispatchInfo when rethrowing …

…from TaskContinuation (mono#19208)

* [corlib] Capture the ExceptionDispatchInfo when rethrowing from TaskContinuation

In `task.GetAwaiter().OnCompleted(action)` if `action` throws, the
`TaskContinuation.RunOrScheduleAction method will catch the exception and then
call `RuntimeAugments.ReportUnhandledException`.  We must not simply throw the
exception again - in that case we will lose all the frames leading up to the
`catch` in `RunOrScheduleAction`.  Instead use ExceptionDispatchInfo to
caputure the original throw.

Addresses mono#19166

* [test] Add regression test

For annoying reasons we can't run this as a simple NUnit test because the
exception is unhandled on some arbitrary threadpool worker thread, and those
don't show up within an NUnit setup.

Additionally because the unhandled exception in the root domain would normally
terminate the application, we need to run this in a new appdomain.

Co-authored-by: Aleksey Kliger <[email protected]>

[2019-12] Bump msbuild to track mono-2019-12 (mono#19205)

[2019-12] Bump msbuild to track mono-2019-12 (mono#19078)

Update mono-extensions

Backport 2020-02 enable embedded ppdb. (mono#19050)

Co-authored-by: Thays Grazia <[email protected]>

Bump bockbuild for Pango nil check fix

Pango nil check fix: https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1069059/

Brings in mono/bockbuild#153

Backport of mono#18936