fix(developer): don't check both setup.exe and setup-redist.exe

Fixes #4354.

The redistributable build should be checking for the existence of either
setup.exe or setup-redist.exe. Note that the only difference between the
two is whether or not the file has a digital signature (as we should not
put a digital signature on an executable that will later have a .zip
appended, rather the final file should be signed).