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/SSDTExtensions.Tests.ps1

@@ -0,0 +1,21 @@
+Describe "SSDTExtensions" {
+#These extensions don't have any proper name in the state.packages.json file, only id is available, which can be found on extension marketplace download page
+
+    if (Test-isWin19) {
+      $testExtenions = @(
+      @{id = "04a86fc2-dbd5-4222-848e-911638e487fe"}
+      @{id = "851E7A09-7B2B-4F06-A15D-BABFCB26B970"}
+      @{id = "717ad572-c4b7-435c-c166-c2969777f718"}
+      )
+
+      It "Extensions id=<id>" -TestCases $testExtenions {
+        $version = Get-VSExtensionVersion -packageName "${id}"
+        $version | Should -Not -BeNullOrEmpty
+      }
+    } else {
+      It "Extension SSDT" {
+        $version = Get-VSExtensionVersion -packageName "SSDT"
+        $version | Should -Not -BeNullOrEmpty
+      }
+    }
+}