emulators/qemu-user-static: update to head as of 2019/11/12

With this update, sendmsg/recvmsg (thus, casper'ized) applications now work
again on mips. Various signal handling issues have also been addressed,
most notably qemu-user-static should no longer deadlock when evaluating
whether printf survives out-of-memory conditions or not.

PR: 224740
Approved by: ler (ports), sbruno (maintainer, implicit)
MFH: 2019Q4