Major changes are:
- Rename `s_wasSystemPolicyDebugPolicy` to `s_allowDebugOverridePolicy` to make it less confusing. Also slightly refactor `HelperSecurity.psm1` and `ConstrainedLanguageDebugger.Tests.ps1` to remove unneeded code. There is no functional change in this commit.
- Remove the unneeded static property `IsInbox`, as PowerShell Core won't be shipped in-box with Windows in the foreseeable feature. Even if we do in future, we won't be needing it because Windows PowerShell will probably be gone by that time.
- Update 'BindRunspace' to avoid getting all commands and unneeded method calls.
- Avoid creating a `IsSafeValueVisitor` every time when `IsScriptBlockInFactASafeHashtable` runs.
Consolidation of all Windows PowerShell work ported to PSCore6
* Added ps1 file import restriction. Refactored InvokeLanguageModeTestingSupportCmdlet to HelpersSecurity module
* JEA loop back fix. Debugger running commands in CL mode.
* Support for new AMSI codes. Changed to use AMSI buffer API. Unhandled exception fix.
* Fixes for module bugs while running in ConstrainedLanguage mode
* Untrusted input tracking work
* Configuration keyword bug fix, PSRP protocol version check for reconstruct reconnect, Sharing InitialSessionState in runspace pool.
* Restricted remote session in UMCI, Applocker detection collision, Help command exposing functions, Null reference exception fix.
* Added mitigation for debugger function exposure
