Make initial Mock cleanup more performant

src/functions/Mock.ps1

@@ -1573,33 +1573,26 @@ function Test-IsClosure {
 }
 
 function Remove-MockFunctionsAndAliases ($SessionState) {
-    # when a test is terminated (e.g. by stopping at a breakpoint and then stoping the execution of the script)
-    # the aliases and bootstrap functions for the currently mocked functions will remain in place
+    # When a test is terminated (e.g. by stopping at a breakpoint and then stoping the execution of the script)
+    # the aliases and bootstrap functions for the currently mocked functions will remain in place.
     # Then on subsequent runs the bootstrap function will be picked up instead of the real command,
     # because there is still an alias associated with it, and the test will fail.
     # So before putting Pester state in place we should make sure that all Pester mocks are gone
-    # by deleting every alias pointing to a function that starts with PesterMock_. Then we also delete the
-    # bootstrap function.
+    # by deleting every alias pointing to a function that starts with PesterMock_.
+    # As a perf optimization we don't delete the bootstrap functions because running Get-Command
+    # in every loaded module has significant overhead (https://github.com/pester/Pester/discussions/2331)
+    # and the PesterMock_ function won't be picked up without an alias.
     $Get_Alias = $script:SafeCommands['Get-Alias']
-    $Get_Command = $script:SafeCommands['Get-Command']
     $Remove_Item = $script:SafeCommands['Remove-Item']
     foreach ($alias in (& $Get_Alias -Definition "PesterMock_*")) {
         & $Remove_Item "alias:/$($alias.Name)"
     }
 
-    foreach ($bootstrapFunction in (& $Get_Command -Name "PesterMock_*")) {
-        & $Remove_Item "function:/$($bootstrapFunction.Name)"
-    }
-
     $ScriptBlock = {
-        param ($Get_Alias, $Get_Command, $Remove_Item)
+        param ($Get_Alias, $Remove_Item)
         foreach ($alias in (& $Get_Alias -Definition "PesterMock_*")) {
             & $Remove_Item "alias:/$($alias.Name)"
         }
-
-        foreach ($bootstrapFunction in (& $Get_Command -Name "PesterMock_*")) {
-            & $Remove_Item "function:/$($bootstrapFunction.Name)"
-        }
     }
 
     # clean up in caller session state
@@ -1618,7 +1611,7 @@ function Remove-MockFunctionsAndAliases ($SessionState) {
         # https://github.com/PowerShell/PowerShell/blob/658837323599ab1c7a81fe66fcd43f7420e4402b/src/System.Management.Automation/engine/runtime/Operations/MiscOps.cs#L51-L55
         # https://github.com/pester/Pester/issues/1921
         if ('Script', 'Manifest' -contains $module.ModuleType -and $null -ne $module.SessionState) {
-            & ($module) $ScriptBlock $Get_Alias $Get_Command $Remove_Item
+            & ($module) $ScriptBlock $Get_Alias $Remove_Item
         }
     }
 }
@@ -1823,13 +1816,13 @@ function Repair-EnumParameters {
     # https://github.com/PowerShell/PowerShell/issues/17546
     $ast = [System.Management.Automation.Language.Parser]::ParseInput("param($ParamBlock)", [ref]$null, [ref]$null)
     $brokenValidateRange = $ast.FindAll({
-        param($node)
-        $node -is [System.Management.Automation.Language.AttributeAst] -and
-        $node.TypeName.Name -match '(?:ValidateRange|System\.Management\.Automation\.ValidateRangeAttribute)$' -and
-        $node.NamedArguments.Count -gt 0 -and
-        # triple checking for broken argument - it won't have a value/expression
-        $node.NamedArguments.ExpressionOmitted -notcontains $false
-    }, $false)
+            param($node)
+            $node -is [System.Management.Automation.Language.AttributeAst] -and
+            $node.TypeName.Name -match '(?:ValidateRange|System\.Management\.Automation\.ValidateRangeAttribute)$' -and
+            $node.NamedArguments.Count -gt 0 -and
+            # triple checking for broken argument - it won't have a value/expression
+            $node.NamedArguments.ExpressionOmitted -notcontains $false
+        }, $false)
 
     if ($brokenValidateRange.Count -eq 0) {
         # No errors found. Return original string