Prefer HarfBuzz to Uniscribe on MS-Windows

* src/w32fns.c (Fx_create_frame, w32_create_tip_frame):
Register the Uniscribe font backend only if HarfBuzz is not
available, or if explicitly requested via frame parameters
or resources.
1 job for harfbuzz in 3 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Test
failed #1960
test-all

00:00:03

 
Name Stage Failure
failed
test-all Test There has been a runner system failure, please try again
Running with gitlab-runner 11.6.0 (f100a208)
on gitlab-runner-docker cff9d373
Using Docker executor with image debian:stretch ...
Pulling docker image debian:stretch ...
Using docker image sha256:8d31923452f8b79ae91b01568d28c90e7d667a9eaff9734c6faeb017b0efa8d0 for debian:stretch ...
ERROR: Job failed (system failure): Error response from daemon: failed to start shim: exec: "docker-containerd-shim": executable file not found in $PATH: unknown (executor_docker.go:1018:0s)