Roll HarfBuzz to 1.4.1

Includes support for specifying OpenType 1.8 font variations axis
parameters.

Baseline updates due to expected advance width differences for some
Khmer combining marks, as well as combining marks placement in
combination with ligatures, due to HarfBuzz commit 1a0f4aa6dfee69236b4.

BUG=679305

Review-Url: https://codereview.chromium.org/2622553002
Cr-Commit-Position: refs/heads/master@{#444707}