Remove tab character like other "zero-width" characters
Uniscribe does that, this make comparing results to Uniscribe
easier.
diff --git a/src/hb-unicode-private.hh b/src/hb-unicode-private.hh
index 519fa0b..ddba1ac 100644
--- a/src/hb-unicode-private.hh
+++ b/src/hb-unicode-private.hh
@@ -149,7 +149,8 @@
(ch >= 0x202A && ch <= 0x202E) ||
(ch >= 0x2060 && ch <= 0x2063) ||
(ch == 0x2028)
- )) || unlikely (ch == 0x00AD
+ )) || unlikely (ch == 0x0009
+ || ch == 0x00AD
|| ch == 0x034F
|| ch == 0xFEFF);
}