[Xamarin.Android.Build.Tasks] fix for MonoPackageManager.java from 16.1

[jonathanpeppers]

Fixes: http://work.devdiv.io/899432

There is a #deletebinobj problem if you take an existing project built
with 16.1 and build with 16.2/master.

1. File > New > Android App in 16.1.
2. Build
3. Open in 16.2, build.

Get an error such as:

obj\Debug\90\android\src\mono\MonoPackageManager_Resources.java(2,8):  error: duplicate class: mono.MonoPackageManager_Resources
public class MonoPackageManager_Resources {

Reviewing obj\Debug\90\android\src\mono, there is a
MonoPackageManager.java and MonoPackageManager_Resources.java that
have a duplicate class.

In 5a9d1a6, we had already tried to fix this, but the
_CleanupOldStaticResources target was not running? It appears that
16.1 is not producing the ApplicationRegistration.java file it is
looking for.

The path we were using for a few files wasn't right:

android\src\mono\app\ApplicationRegistration.java

Should actually be:

android\src\mono\android\app\ApplicationRegistration.java

But then looking at <GenerateJavaStubs/>, we still produce this
file? I think we should instead use NotifyTimeZoneChanges.java for
this check. We don't need to delete, or look for
ApplicationRegistration.java.

Then I found another problem, in that _GeneratePackageManagerJava
and _CompileJava need to re-run. I added the stamp files for these
MSBuild targets to the @(_OldStaticResources) item group to fix
this.

[jonathanpeppers]

I think the build results look the same as recent builds to me:

• Windows: all AOT related
• macOS: network related, and the xunit bcl tests exited