Only build site extensions on main build (#9722)

Author: jkotalik

.azure/pipelines/ci.yml

@@ -297,7 +297,7 @@ jobs:
     agentOs: Windows
     isTestingJob: true
     buildScript: ./eng/scripts/cibuild.cmd
-    buildArgs: -test "/p:SkipIISBackwardsCompatibilityTests=true /p:SkipIISTests=true /p:SkipIISExpressTests=true /p:SkipIISForwardsCompatibilityTests=true /p:RunTemplateTests=false"
+    buildArgs: -test "/p:SkipIISBackwardsCompatibilityTests=true /p:SkipIISTests=true /p:SkipIISExpressTests=true /p:SkipIISForwardsCompatibilityTests=true /p:RunTemplateTests=false /p:BuildSiteExtensions=false"
     beforeBuild:
     - powershell: "& ./src/Servers/IIS/tools/UpdateIISExpressCertificate.ps1; & ./src/Servers/IIS/tools/update_schema.ps1"
       displayName: Setup IISExpress test certificates and schema
@@ -318,7 +318,7 @@ jobs:
     agentOs: Windows
     isTestingJob: true
     buildScript: ./src/ProjectTemplates/build.cmd
-    buildArgs: -ci -test -NoRestore -NoBuild -NoBuilddeps "/p:RunTemplateTests=true"
+    buildArgs: -ci -test -NoRestore -NoBuild -NoBuilddeps "/p:RunTemplateTests=true /p:BuildSiteExtensions=false"
     beforeBuild:
     - powershell:  ./eng/scripts/cibuild.cmd
       displayName: Build Repo

build/repo.props

@@ -8,7 +8,7 @@
     <DisableDefaultTargets>true</DisableDefaultTargets>
     <DisableDefaultItems>true</DisableDefaultItems>
     <BuildSolutions>false</BuildSolutions>
-    <BuildSiteExtensions Condition="'$(TargetRuntimeIdentifier)' == 'win-x64' OR '$(TargetRuntimeIdentifier)' == 'win-x86'">true</BuildSiteExtensions>
+    <BuildSiteExtensions Condition="('$(TargetRuntimeIdentifier)' == 'win-x64' OR '$(TargetRuntimeIdentifier)' == 'win-x86') AND '$(BuildSiteExtensions)' == ''">true</BuildSiteExtensions>
 
     <OverridePackageOutputPath>false</OverridePackageOutputPath>