Adapt default sc.ini to MsCoff by default

[MoonlightSentinel]

The old configuration still used OPTLINk for -m32 which obviously doesn't support MsCoff files. Also added a test file that builds and executes a small program using the configurations in ini and build.d (as allmost all other tests run with -conf=).

CC @thewilsonator

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[MoonlightSentinel]

Ready for review

[maxhaton]

While you're working on this area of dmd it might be good to sort out dmd's behaviour WRT lib. If I understand the bug correctly it actually overwrites the LIB environment variable rather than appending to it.

[MoonlightSentinel]

I think so. Appending the correct path to LIB would enable the linker to find the correct libraries but still fail because dmd then passes MsCoff files to OPTLINK (configured by LINKCMD)