Revert "Make switch statement report correct error position when it fails to evaluate the condition" (#7182)

The fix causes a problem in debugging. When stepping over the scripts in debugging mode, the debugger will stop at the switch statement condition expression twice at the very beginning -- one for evaluating the condition, and one for iterating the condition.

src/System.Management.Automation/engine/parser/Compiler.cs

@@ -4189,7 +4189,10 @@ namespace System.Management.Automation.Language
             // $foreach/$switch = GetEnumerator $enumerable
             var enumerable = NewTemp(typeof(object), "enumerable");
             temps.Add(enumerable);
-            exprs.Add(UpdatePosition(stmt.Condition));
+            if (generatingForeach)
+            {
+                exprs.Add(UpdatePosition(stmt.Condition));
+            }
             exprs.Add(
                 Expression.Assign(enumerable,
                                   GetRangeEnumerator(stmt.Condition.GetPureExpression())

test/powershell/Language/Scripting/ErrorPosition.Tests.ps1

@@ -1,51 +0,0 @@
-# Copyright (c) Microsoft Corporation. All rights reserved.
-# Licensed under the MIT License.
-
-Describe "Error position Tests" -Tags "CI" {
-    It "switch condition evaluation failure should report correct error position" {
-        $testFile = Join-Path $TestDrive "SwitchError1.ps1"
-        Set-Content -Path $testFile -Encoding Ascii -Value @'
-$test = 1
-switch ($null[0]) {
-    "a" {};
-}
-'@
-        try { & $testFile } catch { $errorRecord = $_ }
-        $errorRecord | Should -Not -BeNullOrEmpty
-        $errorRecord.ScriptStackTrace | Should -Match "SwitchError1.ps1: line 2"
-    }
-
-    It "switch condition MoveNext failure should report correct error position" {
-        $code = @'
-using System;
-using System.Collections.Generic;
-namespace SwitchTest
-{
-    public class Test
-    {
-        public static IEnumerable<string> GetName()
-        {
-            yield return "Hello world";
-            throw new ArgumentException();
-        }
-    }
-}
-'@
-        $testFile = Join-Path $TestDrive "SwitchError2.ps1"
-        Set-Content -Path $testFile -Encoding Ascii -Value @'
-$test = 1
-$enumerable = [SwitchTest.Test]::GetName()
-switch ($enumerable) {
-    "hello world" { $test = 1; $_ }
-    "Yay" { $test = 2; $_ }
-}
-'@
-        if (-not ("SwitchTest.Test" -as [type])) {
-            Add-Type -TypeDefinition $code
-        }
-        
-        try { & $testFile > $null } catch { $errorRecord = $_ }
-        $errorRecord | Should -Not -BeNullOrEmpty
-        $errorRecord.ScriptStackTrace | Should -Match "SwitchError2.ps1: line 3"
-    }
-}