Fix HttpStress and SslStress missing apphost build error (#115352)

Co-authored-by: Miha Zupan <mizupan@microsoft.com>

Author: MihaZupan

src/libraries/System.Net.Http/tests/StressTests/HttpStress/Directory.Build.props

@@ -15,5 +15,6 @@
         <MicrosoftNetCoreAppFrameworkName>Microsoft.NETCore.App</MicrosoftNetCoreAppFrameworkName>
         <MicrosoftNetCoreAppRefPackDir Condition="'$(MicrosoftNetCoreAppRefPackDir)' == ''" >$(RepositoryRoot)artifacts/bin/microsoft.netcore.app.ref/</MicrosoftNetCoreAppRefPackDir>
         <MicrosoftNetCoreAppRuntimePackDir Condition="'$(MicrosoftNetCoreAppRuntimePackDir)' == ''">$(RepositoryRoot)artifacts/bin/microsoft.netcore.app.runtime.$(OutputRID)/$(Configuration)/</MicrosoftNetCoreAppRuntimePackDir>
+        <UseLocalAppHostPack>false</UseLocalAppHostPack>
     </PropertyGroup>
 </Project>

src/libraries/System.Net.Security/tests/StressTests/SslStress/Directory.Build.props

@@ -15,5 +15,6 @@
         <MicrosoftNetCoreAppFrameworkName>Microsoft.NETCore.App</MicrosoftNetCoreAppFrameworkName>
         <MicrosoftNetCoreAppRefPackDir Condition="'$(MicrosoftNetCoreAppRefPackDir)' == ''" >$(RepositoryRoot)artifacts/bin/microsoft.netcore.app.ref/</MicrosoftNetCoreAppRefPackDir>
         <MicrosoftNetCoreAppRuntimePackDir Condition="'$(MicrosoftNetCoreAppRuntimePackDir)' == ''">$(RepositoryRoot)artifacts/bin/microsoft.netcore.app.runtime.$(OutputRID)/$(Configuration)/</MicrosoftNetCoreAppRuntimePackDir>
+        <UseLocalAppHostPack>false</UseLocalAppHostPack>
     </PropertyGroup>
 </Project>