Use generic shaper for Buhid

As requested by Jonathan Kew.

We need to devise a better mechanism to choose which scripts to
pass through the Indic shaper.  Moreover, currently we are storing
data for some scripts in the Indic shaper that are not even going
through that shaper.  Need to find a better way...

src/hb-ot-shape-complex-private.hh

@@ -88,6 +88,7 @@ hb_ot_shape_complex_categorize (const hb_segment_properties_t *props)
     /* Simple? */
     case HB_SCRIPT_BATAK:
     case HB_SCRIPT_BRAHMI:
+    case HB_SCRIPT_BUHID:
     case HB_SCRIPT_HANUNOO:
     case HB_SCRIPT_MEETEI_MAYEK:
     case HB_SCRIPT_SAURASHTRA:
@@ -112,7 +113,6 @@ hb_ot_shape_complex_categorize (const hb_segment_properties_t *props)
     case HB_SCRIPT_BALINESE:
     case HB_SCRIPT_BENGALI:
     case HB_SCRIPT_BUGINESE:
-    case HB_SCRIPT_BUHID:
     case HB_SCRIPT_CHAM:
     case HB_SCRIPT_DEVANAGARI:
     case HB_SCRIPT_GUJARATI: