[PT Run] Improvements on EnvironmentHelper and deletion of old env vars (#13363)

* Improve log message

* New method

* changes made so far

* code cleanup and new method

* fix method name

* final changes so far

* Code cleanup and typo fixes

* fix bugs and code cleanup

* fix typo

* rename Method

* fix cast exception

* fix type casting

* exception handling for testing

* Update path var name#

* make collections case insensitive

* fix spelling

* add code to update names

* improve comments

* exception handling and logging

* update comments

* final changes

* fix typo

* Update comments

* add summary to IsRunningAsSystem method

* update var and fix typos

* Update code

* add log warning for protected vars

* add comment

* fix bugs

* small change

* Update log text

* Skipp logging for USERNAME

.github/actions/spell-check/expect.txt

@@ -733,6 +733,7 @@ Hardlines
 HARDWAREINPUT
 hashcode
 Hashset
+Hashtable
 HASHVAL
 hbitmap
 hbmp