Enable UseSizeOptimizedLinq by default on native AOT (#113214)

The motivation is:

* This has been enabled by default on mobile platforms for several releases and it wasn't a source of issues
* It is easy to opt out of it. (That cannot be said about mobile platforms in the past that hardcoded it at repo build).
* Doesn't have measurable throughput impact on any ASP.NET scenarios we measure perf of.
* It is a meaningful size saving (seen 5+%).

Author: MichalStrehovsky

src/coreclr/nativeaot/BuildIntegration/Microsoft.NETCore.Native.targets

@@ -38,6 +38,7 @@ The .NET Foundation licenses this file to you under the MIT license.
     <EventSourceSupport Condition="$(EventSourceSupport) == ''">false</EventSourceSupport>
     <UseWindowsThreadPool Condition="'$(UseWindowsThreadPool)' == '' and '$(_targetOS)' == 'win'">true</UseWindowsThreadPool>
     <DynamicCodeSupport Condition="'$(DynamicCodeSupport)' == ''">false</DynamicCodeSupport>
+    <UseSizeOptimizedLinq Condition="'$(UseSizeOptimizedLinq)' == ''">true</UseSizeOptimizedLinq>
   </PropertyGroup>
 
   <!-- Configure LINQ expressions -->