After a `BlockAllOperations`, the restoration of the `updateRealm`
instance is not instance. It is posted to a `SynchronizationContext`.
The assertion which has been removed in this commit was assuming it
would always be an immediate operation.
To ensure this works as expected, I've tracked the initialised state via
a new `bool`.
```csharp
System.TimeoutException : Attempting to block for migration took too long.
1) Host threw exception System.AggregateException: One or more errors occurred. (: )
---> NUnit.Framework.AssertionException: :
at osu.Framework.Logging.ThrowingTraceListener.Fail(String message1, String message2)
at System.Diagnostics.TraceInternal.Fail(String message, String detailMessage)
at System.Diagnostics.TraceInternal.TraceProvider.Fail(String message, String detailMessage)
at System.Diagnostics.Debug.Fail(String message, String detailMessage)
at osu.Game.Database.RealmAccess.BlockAllOperations() in /opt/buildagent/work/ecd860037212ac52/osu.Game/Database/RealmAccess.cs:line 813
at osu.Game.OsuGameBase.<>c__DisplayClass108_1.<Migrate>b__0() in /opt/buildagent/work/ecd860037212ac52/osu.Game/OsuGameBase.cs:line 449
at osu.Framework.Threading.ScheduledDelegate.RunTaskInternal()
at osu.Framework.Threading.Scheduler.Update()
at osu.Framework.Graphics.Drawable.UpdateSubTree()
at osu.Framework.Graphics.Containers.CompositeDrawable.UpdateSubTree()
```
https://teamcity.ppy.sh/buildConfiguration/Osu_Build/322?hideProblemsFromDependencies=false&hideTestsFromDependencies=false&expandBuildTestsSection=true
I can't find a better way to do this. It's very hard to trigger an
actual failure in the import process these days. For now I've just made
this work with the new assumptions. May be worth removing the test in
the future if this ever backfires.
Not only does this combine the check into one location, but it also adds
a check on the global `WorkingBeatmap` being updated, which is the only
way I can see the following failure happening:
```csharp
05:19:07 osu.Game.Tests: osu.Game.Tests.Visual.Editing.TestSceneEditorBeatmapCreation.TestAddAudioTrack
05:19:07 Failed TestAddAudioTrack [161 ms]
05:19:07 Error Message:
05:19:07 TearDown : System.NullReferenceException : Object reference not set to an instance of an object.
05:19:07 Stack Trace:
05:19:07 --TearDown
05:19:07 at osu.Game.Database.ModelManager`1.<>c__DisplayClass7_0.<AddFile>b__0(TModel managed) in C:\BuildAgent\work\ecd860037212ac52\osu.Game\Database\ModelManager.cs:line 36
05:19:07 at osu.Game.Database.ModelManager`1.<>c__DisplayClass8_0.<performFileOperation>b__0(Realm realm) in C:\BuildAgent\work\ecd860037212ac52\osu.Game\Database\ModelManager.cs:line 49
05:19:07 at osu.Game.Database.RealmExtensions.Write(Realm realm, Action`1 function) in C:\BuildAgent\work\ecd860037212ac52\osu.Game\Database\RealmExtensions.cs:line 14
05:19:07 at osu.Game.Database.ModelManager`1.performFileOperation(TModel item, Action`1 operation) in C:\BuildAgent\work\ecd860037212ac52\osu.Game\Database\ModelManager.cs:line 46
05:19:07 at osu.Game.Database.ModelManager`1.AddFile(TModel item, Stream contents, String filename) in C:\BuildAgent\work\ecd860037212ac52\osu.Game\Database\ModelManager.cs:line 36
05:19:07 at osu.Game.Screens.Edit.Setup.ResourcesSection.ChangeAudioTrack(FileInfo source) in C:\BuildAgent\work\ecd860037212ac52\osu.Game\Screens\Edit\Setup\ResourcesSection.cs:line 115
05:19:07 at osu.Game.Tests.Visual.Editing.TestSceneEditorBeatmapCreation.<TestAddAudioTrack>b__13_0() in C:\BuildAgent\work\ecd860037212ac52\osu.Game.Tests\Visual\Editing\TestSceneEditorBeatmapCreation.cs:line 101
05:19:07 at osu.Framework.Testing.Drawables.Steps.AssertButton.checkAssert()
05:19:07 at osu.Framework.Testing.Drawables.Steps.StepButton.PerformStep(Boolean userTriggered)
05:19:07 at osu.Framework.Testing.TestScene.runNextStep(Action onCompletion, Action`1 onError, Func`2 stopCondition)
```
