Update SDK to 8.0.100-preview.6.23305.3 (#48619)

* Update SDK to 8.0.100-preview.6.23305.3

* Fix build for new 8.0 SDK

- Add static keyword for method that doesn't need to be an instance method.
- Change workaround for https://github.com/dotnet/linker/issues/3175 to use net7.0 instead of net8.0. The ILLink.Analysis package no longer ships in net8.0. So use net7.0, like the rest of the "unsupported" TFMs use.

NuGet.config

@@ -5,6 +5,7 @@
     <add key="dotnet-eng" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-eng/nuget/v3/index.json" />
     <add key="dotnet-tools" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-tools/nuget/v3/index.json" />
     <add key="dotnet8" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet8/nuget/v3/index.json" />
+    <add key="dotnet7" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet7/nuget/v3/index.json" />
     <add key="dotnet8-transport" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet8-transport/nuget/v3/index.json" />
     <add key="dotnet-public" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-public/nuget/v3/index.json" />
     <!-- Used for the SiteExtension bits that are included in the 8.0 build -->

eng/tools/GenerateFiles/Directory.Build.targets.in

@@ -139,7 +139,7 @@
           BeforeTargets="ProcessFrameworkReferences">
     <ItemGroup>
       <KnownILLinkPack Include="@(KnownILLinkPack)"
-                       Condition="'%(TargetFramework)' == '${DefaultNetCoreTargetFramework}'"
+                       Condition="'%(TargetFramework)' == 'net7.0'"
                        TargetFramework="netstandard2.1"
                        ILLinkPackVersion="%(KnownILLinkPack.ILLinkPackVersion)" />
     </ItemGroup>

global.json

@@ -1,9 +1,9 @@
 {
   "sdk": {
-    "version": "8.0.100-preview.5.23275.15"
+    "version": "8.0.100-preview.6.23305.3"
   },
   "tools": {
-    "dotnet": "8.0.100-preview.5.23275.15",
+    "dotnet": "8.0.100-preview.6.23305.3",
     "runtimes": {
       "dotnet/x86": [
         "$(MicrosoftNETCoreBrowserDebugHostTransportVersion)"

src/Mvc/Mvc.Core/src/Routing/ActionConstraintMatcherPolicy.cs

@@ -151,7 +151,7 @@ internal sealed class ActionConstraintMatcherPolicy : MatcherPolicy, IEndpointSe
         return EvaluateActionConstraintsCore(httpContext, candidateSet, items, startingOrder: null);
     }
 
-    private IReadOnlyList<(int index, ActionSelectorCandidate candidate)>? EvaluateActionConstraintsCore(
+    private static IReadOnlyList<(int index, ActionSelectorCandidate candidate)>? EvaluateActionConstraintsCore(
         HttpContext httpContext,
         CandidateSet candidateSet,
         IReadOnlyList<(int index, ActionSelectorCandidate candidate)> items,