Fix docker build ngen errors

4.7.1-windowsservercore-ltsc2016/runtime/Dockerfile

@@ -14,6 +14,7 @@ RUN Add-WindowsFeature Web-Server; `
 RUN Invoke-WebRequest https://api.nuget.org/packages/microsoft.net.compilers.2.3.1.nupkg -OutFile c:\microsoft.net.compilers.2.3.1.zip ; `	
     Expand-Archive -Path c:\microsoft.net.compilers.2.3.1.zip -DestinationPath c:\RoslynCompilers ; `
     Remove-Item c:\microsoft.net.compilers.2.3.1.zip -Force ; `
+    &set COMPLUS_NGenProtectedProcess_FeatureEnabled=0 ; `
     &C:\Windows\Microsoft.NET\Framework64\v4.0.30319\ngen.exe update ; `
     &C:\Windows\Microsoft.NET\Framework\v4.0.30319\ngen.exe update ; `
     &C:\Windows\Microsoft.NET\Framework64\v4.0.30319\ngen.exe install c:\RoslynCompilers\tools\csc.exe /ExeConfig:c:\RoslynCompilers\tools\csc.exe | `

4.7.2-windowsservercore-1709/runtime/Dockerfile

@@ -14,6 +14,7 @@ RUN Add-WindowsFeature Web-Server; `
 RUN Invoke-WebRequest https://api.nuget.org/packages/microsoft.net.compilers.2.3.1.nupkg -OutFile c:\microsoft.net.compilers.2.3.1.zip ; `	
     Expand-Archive -Path c:\microsoft.net.compilers.2.3.1.zip -DestinationPath c:\RoslynCompilers ; `
     Remove-Item c:\microsoft.net.compilers.2.3.1.zip -Force ; `
+    &set COMPLUS_NGenProtectedProcess_FeatureEnabled=0 ; `
     &C:\Windows\Microsoft.NET\Framework64\v4.0.30319\ngen.exe install c:\RoslynCompilers\tools\csc.exe /ExeConfig:c:\RoslynCompilers\tools\csc.exe | `
     &C:\Windows\Microsoft.NET\Framework64\v4.0.30319\ngen.exe install c:\RoslynCompilers\tools\vbc.exe /ExeConfig:c:\RoslynCompilers\tools\vbc.exe  | `
     &C:\Windows\Microsoft.NET\Framework64\v4.0.30319\ngen.exe install c:\RoslynCompilers\tools\VBCSCompiler.exe /ExeConfig:c:\RoslynCompilers\tools\VBCSCompiler.exe | `

4.7.2-windowsservercore-ltsc2016/runtime/Dockerfile

@@ -14,6 +14,7 @@ RUN Add-WindowsFeature Web-Server; `
 RUN Invoke-WebRequest https://api.nuget.org/packages/microsoft.net.compilers.2.3.1.nupkg -OutFile c:\microsoft.net.compilers.2.3.1.zip ; `	
     Expand-Archive -Path c:\microsoft.net.compilers.2.3.1.zip -DestinationPath c:\RoslynCompilers ; `
     Remove-Item c:\microsoft.net.compilers.2.3.1.zip -Force ; `
+    &set COMPLUS_NGenProtectedProcess_FeatureEnabled=0 ; `
     &C:\Windows\Microsoft.NET\Framework64\v4.0.30319\ngen.exe update ; `
     &C:\Windows\Microsoft.NET\Framework\v4.0.30319\ngen.exe update ; `
     &C:\Windows\Microsoft.NET\Framework64\v4.0.30319\ngen.exe install c:\RoslynCompilers\tools\csc.exe /ExeConfig:c:\RoslynCompilers\tools\csc.exe | `