cmcmd: Simplify vs_link_{exe,dll} output encoding logic

Revise commit 7e359823c9 (MSVC: Preserve linker output encoding,
2018-08-03, v3.13.0-rc1~223^2) using the approach from commit f7a5f28318
(cmake: Fix '-E cat' command for binary files on Windows, 2020-10-13,
v3.18.5~5^2).