refactor: remove IsWindows compatibility shim test

The $IsWindows PS 5.1 shim is being removed from Build-PSModule since
PSModule targets PowerShell LTS (7.6+). Remove the corresponding test
context and update the test repo output fixture.

Author: MariusStorhaug

src/tests/Module/PSModule/PSModule.Tests.ps1

@@ -89,20 +89,6 @@ Describe 'PSModule - Module tests' {
         }
     }
 
-    Context 'Framework - IsWindows compatibility shim' {
-        BeforeAll {
-            Import-Module -Name $moduleManifestPath -Force
-            $script:moduleRef = Get-Module -Name $moduleName
-        }
-        It 'Should have $IsWindows defined in the module scope' {
-            # The framework injects "$IsWindows = $true" for PowerShell 5.1 (Desktop edition).
-            # On PS 7+ (Core), $IsWindows is a built-in automatic variable.
-            # The variable is set inside the module scope and is not exported, so we must check from within the module.
-            $isWindowsDefined = & $script:moduleRef { Get-Variable -Name 'IsWindows' -ErrorAction SilentlyContinue }
-            $isWindowsDefined | Should -Not -BeNullOrEmpty -Because 'the framework injects a compatibility shim for PS 5.1'
-        }
-    }
-
     Context 'Framework - Type accelerator registration' -Skip:(-not $hasClassExporter) {
         BeforeAll {
             Import-Module -Name $moduleManifestPath -Force

tests/outputTestRepo/outputs/module/PSModuleTest/PSModuleTest.psm1

@@ -1,24 +1,10 @@
 [Diagnostics.CodeAnalysis.SuppressMessageAttribute('PSAvoidLongLines', '', Justification = 'Contains long links.')]
-[Diagnostics.CodeAnalysis.SuppressMessageAttribute(
-    'PSAvoidAssignmentToAutomaticVariable', 'IsWindows',
-    Justification = 'IsWindows does not exist in PS5.1'
-)]
-[Diagnostics.CodeAnalysis.SuppressMessageAttribute(
-    'PSUseDeclaredVarsMoreThanAssignments', 'IsWindows',
-    Justification = 'IsWindows does not exist in PS5.1'
-)]
 [CmdletBinding()]
 param()
 
 $scriptName = $MyInvocation.MyCommand.Name
 Write-Debug "[$scriptName] Importing module"
 
-#region - IsWindows compatibility shim
-if ($PSEdition -eq 'Desktop') {
-    $IsWindows = $true
-}
-#endregion - IsWindows compatibility shim
-
 #region - Data import
 Write-Debug "[$scriptName] - [data] - Processing folder"
 $dataFolder = (Join-Path $PSScriptRoot 'data')