MSVC: Fix linking of DLLs on WinCE (#15013)

On WinCE we must link both shared libraries and executables with the
/subsystem:windowsce flag.  Teach Platform/Windows-MSVC to pass it
to the linker in both cases.

Suggested-by: Gunnar Roth <gunnar.roth@gmx.de>
Merge topic 'wince-fix-dll-linking' into next

7e1283e4 MSVC: Fix linking of DLLs on WinCE (#15013)