debug/pe: use ws2_32.dll in TestImportTableInUnknownSection

Apparently (see
https://github.com/golang/go/issues/27904#issuecomment-442140627
for details) kernel32.dll file is not present on windows/arm, so
use ws2_32.dll instead. ws2_32.dll imports table also lives in
'.rdata' section, so ws2_32.dll is as good as kernel32.dll for
testing issue #16103.

Updates #27904

Change-Id: Ibc72b24eea9a4d85abd371ffdcf00442e711b745
Reviewed-on: https://go-review.googlesource.com/c/151480


Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>