Revert "[One .NET] $(AndroidEnablePreloadAssemblies)=False by default"

This reverts commit d13d0f9.

I also updated a test that was triggering an issue with
`$(AndroidEnablePreloadAssemblies)`. It was originally crashing with:

    Java.Lang.RuntimeException: Unable to start activity ComponentInfo{com.xamarin.classlibrarymainlauncherruns/com.xamarin.classlibrarymainlauncherruns.MainActivity}: android.view.InflateException: Binary XML file line #1 in com.xamarin.classlibrarymainlauncherruns:layout/foo: Binary XML file line #1: You must supply a layout_width attribute.
    ---> Android.Views.InflateException: Binary XML file line #1 in com.xamarin.classlibrarymainlauncherruns:layout/foo: Binary XML file line #1: You must supply a layout_width attribute.
    ---> Java.Lang.UnsupportedOperationException: Binary XML file line #1: You must supply a layout_width attribute.
    --- End of managed Java.Lang.UnsupportedOperationException stack trace ---
    java.lang.UnsupportedOperationException: Binary XML file line #1: You must supply a layout_width attribute.

I fixed the invalid XML in `foo.xml`, so the test will get a *better*
crash going forward:

    Process: com.xamarin.classlibrarymainlauncherruns, PID: 2993
    android.runtime.JavaProxyThrowable: System.NullReferenceException: Object reference not set to an instance of an object
        at MyLibrary.MainActivity.OnCreate(Bundle bundle)
        at Android.App.Activity.n_OnCreate_Landroid_os_Bundle_(IntPtr jnienv, IntPtr native__this, IntPtr native_savedInstanceState)
        at com.xamarin.classlibrarymainlauncherruns.MainActivity.n_onCreate(Native Method)
        at com.xamarin.classlibrarymainlauncherruns.MainActivity.onCreate(MainActivity.java:29)
        at android.app.Activity.performCreate(Activity.java:8000)
        at android.app.Activity.performCreate(Activity.java:7984)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1309)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3422)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)

This way we won't be chasing invalid XML going forward.

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/BuildTest.cs

@@ -3932,11 +3932,7 @@ public void PackageNamingPolicy ([Values ("LowercaseMD5", "LowercaseCrc64")] str
 				Assert.IsTrue (b.Build (proj), "build should have succeeded.");
 				var environment = b.Output.GetIntermediaryPath (Path.Combine ("__environment__.txt"));
 				FileAssert.Exists (environment);
-				if (Builder.UseDotNet) {
-					Assert.AreEqual ($"__XA_PACKAGE_NAMING_POLICY__={packageNamingPolicy}{Environment.NewLine}mono.enable_assembly_preload=0", File.ReadAllText (environment).Trim ());
-				} else {
-					Assert.AreEqual ($"__XA_PACKAGE_NAMING_POLICY__={packageNamingPolicy}", File.ReadAllText (environment).Trim ());
-				}
+				Assert.AreEqual ($"__XA_PACKAGE_NAMING_POLICY__={packageNamingPolicy}", File.ReadAllText (environment).Trim ());
 			}
 		}
 

src/Xamarin.Android.Build.Tasks/Xamarin.Android.Common.targets

@@ -290,8 +290,7 @@ Copyright (C) 2011-2012 Xamarin. All rights reserved.
 	<AndroidMakeBundleKeepTemporaryFiles Condition=" '$(AndroidMakeBundleKeepTemporaryFiles)' == '' ">False</AndroidMakeBundleKeepTemporaryFiles>
 
 	<!-- If true it will cause all the assemblies in the apk to be preloaded on startup time -->
-	<_AndroidEnablePreloadAssembliesDefault Condition=" '$(UsingAndroidNETSdk)' == 'true' ">False</_AndroidEnablePreloadAssembliesDefault>
-	<_AndroidEnablePreloadAssembliesDefault Condition=" '$(UsingAndroidNETSdk)' != 'true' ">True</_AndroidEnablePreloadAssembliesDefault>
+        <_AndroidEnablePreloadAssembliesDefault>True</_AndroidEnablePreloadAssembliesDefault>
 	<AndroidEnablePreloadAssemblies Condition=" '$(AndroidEnablePreloadAssemblies)' == '' ">$(_AndroidEnablePreloadAssembliesDefault)</AndroidEnablePreloadAssemblies>
 	<_NativeAssemblySourceDir>$(IntermediateOutputPath)android\</_NativeAssemblySourceDir>
 	<_AndroidUseNewTypemaps>True</_AndroidUseNewTypemaps>

tests/MSBuildDeviceIntegration/Tests/DebuggingTest.cs

@@ -102,7 +102,13 @@ public void ClassLibraryMainLauncherRuns ()
 			// Remove the default MainActivity.cs & AndroidResources
 			app.AndroidResources.Clear ();
 			app.AndroidResources.Add (new AndroidItem.AndroidResource ("Resources\\layout\\foo.xml") {
-				TextContent = () => "<?xml version=\"1.0\" encoding=\"utf-8\" ?><LinearLayout xmlns:android=\"http://schemas.android.com/apk/res/android\" />"
+				TextContent = () =>
+@"<?xml version=""1.0"" encoding=""utf-8""?>
+<LinearLayout
+  xmlns:android=""http://schemas.android.com/apk/res/android""
+  android:layout_width=""fill_parent""
+  android:layout_height=""wrap_content""
+/>"
 			});
 			app.Sources.Remove (app.GetItem ("MainActivity.cs"));