[Lazarus] GetAllFilesMask / AllFilesMask

[Juha Manninen]

In rev. #40849 I replaced GetAllFilesMask with AllFilesMask everywhere.
GetAllFilesMask is defined in LCL, AllFilesMask is defined in FPC's libs.
It was meant to be a cleanup and removal of duplicate code. It seems
that it was wrong. AllFilesMask is '*' on Windows, too.
GetAllFilesMask returned *.* on Windows.

There is a bug somewhere, IMO it is in FPC. AllFilesMask is related to
file operations.
It should not be different between LCL and other code using FPC.

'*:*' is typically used on Windows and FindFirst/FindNext return also
files without suffix when it is used.
I just fixed TFileSearcher to match the logic (issue #24306).

Juha