Roll harfbuzz to 2.7.1

Picks up the fix for https://github.com/harfbuzz/harfbuzz/issues/2516

Change-Id: I60828280ac51c45cb4eb4054077a2979924c6799
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/harfbuzz/+/418335
Reviewed-by: Jason Simmons <jsimmons@google.com>
91 files changed