This PR adds type inference support for the 'MemberName' parameterset for Foreach-Object.
Both of the following should work:
```
Get-Process | % {$_.MainModule} | % Com<Tab>
Get-Process | % MainModule | % Com<Tab>
```
Before this change, only the first line worked, this PR addresses the second line.
Fixes#2596
* Caching the parent id of the current process
In certain scenarios, like a domain joined machine with an executionpolicy set via GPO, a lot of checks are done for the ExecutionPolicy, and this is in the hot path.
* Caching HasGPScriptParent.
It is expensive to determine if a script was run as a result of applying a group policy. This does not change during the lifetime of a process.
This only affect the scenario when an execution policy has been set by a group policy.
* Using available Microsoft.PowerShell.ProcessCodeMethods.GetParentPid
This makes it possibe to write for example
[ValidatePattern('[A-Z]:', ErrorMessage='The Drive should be specified as a single letter followed by a colon, for example "D:"')]
[string] $Drive,
The element being validated is also passed, so {0} can be used in the custom error message
* Refactoring ParsePathCommand.cs (SplitPathCommand) for readability
- Using auto properties when no when there is no logic in getter/setter
- Removing unused code
- Removing redundant qualifiers
- Removing Redundant initializers
* Add -Extension and -Leafbase switches to Split-Path cmdlet
- Extension and LeafBase are specializations of Leaf, and uses System.IO.Path.GetExtension and System.IO.Path.GetFilenameWithoutExtension to extract parts from the Leaf
* Adding tests for Split-Path -LeafBase and Split-Path -Extension
Staffan Gustafsson