fix valgrind warning
fix valgrind warning

For the bigpcre test we generate a line that won't fit in the stack
buffer.  We were using the return value from vsnprintf to size the
write, but this is the non-truncated length.

Measure the string again and ensure that it has a trailing newline

bhamiltoncx/watchman,sdgdsffdsfff/watchman,exponentjs/watchman,nodakai/watchman,kwlzn/watchman,sdgdsffdsfff/watchman,phmx/watchman,yun63/watchman,yangeagle/watchman,supriyantomaftuh/watchman,wez/watchman,dhruvsinghal/watchman,webmasteraxe/watchman,bitemyapp/watchman,yangeagle/watchman,alanwill/watchman,phmx/watchman,Ziriax/watchman,montogeek/watchman,michalliu/watchman,alanwill/watchman,windofthesky/watchman,supriyantomaftuh/watchman,bitemyapp/watchman,michalliu/watchman,twitter/watchman,nodakai/watchman,kevinsawicki/watchman,webmasteraxe/watchman,facebook/watchman,nodakai/watchman,michalliu/watchman,hanhailong/watchman,yonglehou/watchman,dhruvsinghal/watchman,hanhailong/watchman,dhruvsinghal/watchman,windofthesky/watchman,yun63/watchman,Jonekee/watchman,yangeagle/watchman,dhruvsinghal/watchman,montogeek/watchman,bhamiltoncx/watchman,besarthoxhaj/watchman,phmx/watchman,facebook/watchman,kevinsawicki/watchman,bhamiltoncx/watchman,bhamiltoncx/watchman,dcolascione/laptop-watchman,kevinsawicki/watchman,Ziriax/watchman,yun63/watchman,webmasteraxe/watchman,yun63/watchman,supriyantomaftuh/watchman,facebook/watchman,yonglehou/watchman,exponentjs/watchman,masoncloud/watchman,hanhailong/watchman,supriyantomaftuh/watchman,alanwill/watchman,wez/watchman,webmasteraxe/watchman,bitemyapp/watchman,wez/watchman,webmasteraxe/watchman,bitemyapp/watchman,phmx/watchman,wez/watchman,kevinsawicki/watchman,Jonekee/watchman,bitemyapp/watchman,twitter/watchman,windofthesky/watchman,hanhailong/watchman,twitter/watchman,nodakai/watchman,montogeek/watchman,montogeek/watchman,twitter/watchman,Jonekee/watchman,Ziriax/watchman,webmasteraxe/watchman,kevinsawicki/watchman,sdgdsffdsfff/watchman,besarthoxhaj/watchman,wez/watchman,michalliu/watchman,dhruvsinghal/watchman,michalliu/watchman,windofthesky/watchman,dcolascione/laptop-watchman,supriyantomaftuh/watchman,Jonekee/watchman,windofthesky/watchman,alanwill/watchman,wez/watchman,exponentjs/watchman,kevinsawicki/watchman,yonglehou/watchman,twitter/watchman,facebook/watchman,exponentjs/watchman,masoncloud/watchman,bhamiltoncx/watchman,michalliu/watchman,besarthoxhaj/watchman,twitter/watchman,dhruvsinghal/watchman,yangeagle/watchman,twitter/watchman,montogeek/watchman,alanwill/watchman,supriyantomaftuh/watchman,dcolascione/laptop-watchman,Jonekee/watchman,kwlzn/watchman,amasad/watchman,yun63/watchman,yangeagle/watchman,montogeek/watchman,yangeagle/watchman,phmx/watchman,sdgdsffdsfff/watchman,yun63/watchman,amasad/watchman,amasad/watchman,yonglehou/watchman,nodakai/watchman,dhruvsinghal/watchman,nodakai/watchman,twitter/watchman,dhruvsinghal/watchman,Jonekee/watchman,phmx/watchman,amasad/watchman,besarthoxhaj/watchman,masoncloud/watchman,michalliu/watchman,Ziriax/watchman,facebook/watchman,dcolascione/laptop-watchman,sdgdsffdsfff/watchman,montogeek/watchman,windofthesky/watchman,masoncloud/watchman,besarthoxhaj/watchman,alanwill/watchman,nodakai/watchman,hanhailong/watchman,windofthesky/watchman,facebook/watchman,webmasteraxe/watchman,bhamiltoncx/watchman,dcolascione/laptop-watchman,hanhailong/watchman,yonglehou/watchman,exponentjs/watchman,sdgdsffdsfff/watchman,supriyantomaftuh/watchman,masoncloud/watchman,hanhailong/watchman,amasad/watchman,yonglehou/watchman,supriyantomaftuh/watchman,Ziriax/watchman,exponentjs/watchman,dcolascione/laptop-watchman,bitemyapp/watchman,yonglehou/watchman,dcolascione/laptop-watchman,yonglehou/watchman,yun63/watchman,nodakai/watchman,Jonekee/watchman,michalliu/watchman,amasad/watchman,hanhailong/watchman,amasad/watchman,facebook/watchman,besarthoxhaj/watchman,masoncloud/watchman,kwlzn/watchman,wez/watchman,besarthoxhaj/watchman,Jonekee/watchman,sdgdsffdsfff/watchman,kwlzn/watchman,yun63/watchman,kwlzn/watchman,facebook/watchman,webmasteraxe/watchman,wez/watchman,wez/watchman,masoncloud/watchman,amasad/watchman,dcolascione/laptop-watchman,bitemyapp/watchman,facebook/watchman,nodakai/watchman,kwlzn/watchman,masoncloud/watchman,Ziriax/watchman,yangeagle/watchman,besarthoxhaj/watchman,kevinsawicki/watchman,sdgdsffdsfff/watchman,montogeek/watchman,kwlzn/watchman,bitemyapp/watchman