Replace '== null' with 'is null' and '!= null' with 'is not null'
across 19 core files following modern C# pattern matching conventions.
Only literal null comparisons are changed. Assignments, value
comparisons, and LINQ expressions are left untouched.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
* Update CI to detect the word "skipci"
* Make script compilation errors more verbose
Rather than just giving the line in which the error has been found, return the actual text content of the line itself
* Attempt to bubble up errors in the script chain, so it says the reason for any NotRun errors.
The exception message gets eaten up when the script is running, and an exception happens.
Also put in a default result message for the CmdResult, instead of having it default to null.
* Trim the whitespace off returned script compilation error line
