[master] Update dependencies from dotnet/arcade dotnet/core-setup dotnet/corefx (#17458)

* Update dependencies from https://github.com/dotnet/arcade build 20191018.2

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19518.2
- Microsoft.DotNet.Helix.Sdk - 5.0.0-beta.19518.2

* Update dependencies from https://github.com/dotnet/core-setup build 20191021.2

- Microsoft.NETCore.App - 5.0.0-alpha1.19521.2

* Update dependencies from https://github.com/dotnet/corefx build 20191020.7

- Microsoft.Private.CoreFx.NETCoreApp - 5.0.0-alpha1.19520.7

* Update dependencies from https://github.com/dotnet/arcade build 20191023.3

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19523.3
- Microsoft.DotNet.Helix.Sdk - 5.0.0-beta.19523.3

* Update dependencies from https://github.com/dotnet/core-setup build 20191023.10

- Microsoft.NETCore.App - 5.0.0-alpha1.19523.10

* Update dependencies from https://github.com/dotnet/corefx build 20191023.8

- Microsoft.Private.CoreFx.NETCoreApp - 5.0.0-alpha1.19523.8

* Disable a file system watcher test on mac

See https://github.com/mono/mono/issues/17547

* Reenable tests that were fixed

1 files changed, 11 insertions, 1 deletions

diff --git a/eng/common/build.ps1 b/eng/common/build.ps1
index eb2aedac01d..55dff332044 100644
--- a/eng/common/build.ps1
+++ b/eng/common/build.ps1
@@ -18,6 +18,7 @@ Param(
   [switch] $sign,
   [switch] $pack,
   [switch] $publish,
+  [switch] $clean,
   [switch][Alias('bl')]$binaryLog,
   [switch] $ci,
   [switch] $prepareMachine,
@@ -48,6 +49,7 @@ function Print-Usage() {
     Write-Host "  -pack                   Package build outputs into NuGet packages and Willow components"
     Write-Host "  -sign                   Sign build outputs"
     Write-Host "  -publish                Publish artifacts (e.g. symbols)"
+    Write-Host "  -clean                  Clean the solution"
     Write-Host ""
 
     Write-Host "Advanced settings:"
@@ -112,6 +114,14 @@ function Build {
     @properties
 }
 
+if ($clean) {
+  if(Test-Path $ArtifactsDir) {
+    Remove-Item -Recurse -Force $ArtifactsDir
+    Write-Host "Artifacts directory deleted."
+  }
+  exit 0
+}
+
 try {
   if ($help -or (($null -ne $properties) -and ($properties.Contains("/help") -or $properties.Contains("/?")))) {
     Print-Usage
@@ -123,7 +133,7 @@ try {
     $nodeReuse = $false
   }
 
-  if (($restore) -and ($null -eq $env:DisableNativeToolsetInstalls)) {
+  if ($restore) {
     InitializeNativeTools
   }