[tools] initial version of an MSBuild "fuzzer"

[jonathanpeppers]

The idea is that you can run this tool while having a device/emulator
connected:

tools\msbuild-fuzzer\bin\Debug\msbuild-fuzzer.exe

When running the output looks something like:

DesignTimeBuild
RenameResource
RemoveClass
ChangePackageName
Install
Clean
RemoveClass
Install
Starting: Intent { cmp=com.foo.a82008ffe87dd442d92c47658b392fd55/md52d9cf6333b8e95e8683a477bc589eda5.MainActivity }
TouchRandomFile
Build

The process will stop if an MSBuild error occurs, you should get a
stacktrace and find MSBuild binlogs in:

bin\TestDebug\temp\Fuzzer

So far I have not found problems running this for a while on Mac.

I have found what appears to be Windows Defender locking a file on
Windows:

Xamarin.Forms.targets(91,3): error MSB4018: The "XamlCTask" task failed unexpectedly.
    System.IO.IOException: The process cannot access the file 'obj\Release\90\HelloForms.Android.dll' because it is being used by another process.

Server stack trace:
    at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
    at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath, Boolean checkHost)
    at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share)
    at Mono.Cecil.ModuleDefinition.ReadModule(String fileName, ReaderParameters parameters)
    at Mono.Cecil.AssemblyDefinition.ReadAssembly(String fileName, ReaderParameters parameters)
    at Xamarin.Forms.Build.Tasks.XamlCTask.Execute(IList`1& thrownExceptions)
    at Xamarin.Forms.Build.Tasks.XamlTask.Execute()
    at System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr md, Object[] args, Object server, Object[]& outArgs)
    at System.Runtime.Remoting.Messaging.StackBuilderSink.SyncProcessMessage(IMessage msg)

Exception rethrown at [0]:
    at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
    at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
    at Microsoft.Build.Framework.ITask.Execute()
    at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute()
    at Microsoft.Build.BackEnd.TaskBuilder.<ExecuteInstantiatedTask>d__26.MoveNext() [HelloForms.Android.csproj]

XamlCTask is part of Xamarin.Forms, so it isn't something we can
address in Xamarin.Android.