[cff] Prune more code if HB_NO_OT_FONT_CFF

Part of https://github.com/harfbuzz/harfbuzz/issues/1652

src/hb-ot-cff1-table.cc

diff --git a/src/hb-ot-cff1-table.cc b/src/hb-ot-cff1-table.cc
index 1d97e54..2844f3c 100644
--- a/src/hb-ot-cff1-table.cc
+++ b/src/hb-ot-cff1-table.cc
@@ -305,6 +305,11 @@
 
 bool OT::cff1::accelerator_t::get_extents (hb_codepoint_t glyph, hb_glyph_extents_t *extents) const
 {
+#ifdef HB_NO_OT_FONT_CFF
+  /* XXX Remove check when this code moves to .hh file. */
+  return true;
+#endif
+
   bounds_t  bounds;
 
   if (!_get_bounds (this, glyph, bounds))

src/hb-ot-cff2-table.cc

diff --git a/src/hb-ot-cff2-table.cc b/src/hb-ot-cff2-table.cc
index d2463d7..a1aaef6 100644
--- a/src/hb-ot-cff2-table.cc
+++ b/src/hb-ot-cff2-table.cc
@@ -99,6 +99,11 @@
 					   hb_codepoint_t glyph,
 					   hb_glyph_extents_t *extents) const
 {
+#ifdef HB_NO_OT_FONT_CFF
+  /* XXX Remove check when this code moves to .hh file. */
+  return true;
+#endif
+
   if (unlikely (!is_valid () || (glyph >= num_glyphs))) return false;
 
   unsigned int num_coords;