Migrate validation to Pester (#1249)

* remove Validate-* scripts

* Remove references to validation scripts from .json files

* Separate "It"s by new lines

* Remove new line before the first  "It"

* Separate "It"s by new lines

* remove 32-bit WinAppDriver check

* remove explicit variable definition

Co-authored-by: Sergey Dolin <v-sedoli@micorosoft.com>

images/win/scripts/Tests/WinAppDriver.Tests.ps1

@@ -0,0 +1,10 @@
+Describe "WinAppDriver" {
+  It "WinAppDriver directory exists" {
+    Test-Path -Path "${env:ProgramFiles(x86)}\Windows Application Driver" | Should -BeTrue
+  }
+
+  It "Developer Mode is enabled" {
+    $path = "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\AppModelUnlock";
+    Get-ItemProperty -Path $path | Select-Object -ExpandProperty "AllowDevelopmentWithoutDevLicense" | Should -Be 1
+  }
+}