CMakeDetermineCompilerId: Consider UTF-16 encodings of INFO strings

Our compiler identification source encodes `INFO:compiler[...]` and
similar strings in compiled objects or binaries that we then extract to
get information about the compiler.  With most compilers the strings are
encoded in the binaries as a simple byte sequence.  However, some
compilers use other encodings.  For example, the MS CSharp compiler uses
UTF-16LE and a TI compiler uses UTF-16BE.  Try each encoding.

Fixes: #19459