*.Format.ps1xml files are missing (example: FileSystem.Format.ps1xml) #7973
Description
Steps to reproduce
help about_format.ps1xml says that the *.format.ps1xml files are located in the $PSHOME directory but the format files are missing from that directory (and do not exist in the entire directory tree)
Expected behavior
-----------------
```none
Actual behavior
Environment data
> $PSVersionTable
`Name Value
---- -----
PSVersion 6.1.0
PSEdition Core
GitCommitId 6.1.0
OS Microsoft Windows 10.0.17763
Platform Win32NT
PSCompatibleVersions {1.0, 2.0, 3.0, 4.0...}
PSRemotingProtocolVersion 2.3
SerializationVersion 1.1.0.1
WSManStackVersion 3.0