[tlbuild] makejvf.test test failures

[Hironobu Yamashita]

> 2017/07/23 23:51, Ken Brown <kbrow1i at gmail.com>:
> 
>> I hope the attached patch avoids the test failure,
>> though it may look too ad-hoc.
>> (It’s still ok on x86_64-darwin and win32.)
> 
> It's now OK on Cygwin (both i386 and x86_64).
> 

Thank you for testing, done. (r44880)

Hironobu