crt: Rename msvcrt-common.def.in to crt-aliases.def.in

This file contains definitions of symbol aliases for any CRT library. It is
already used by msvcrt, crtdll and ucrt. So rename msvcrt-common.def.in to
crt-aliases.def.in as new name better match the purpose of the file.

Signed-off-by: Martin Storsjö <martin@martin.st>