[CoverageFormat2] Remove hand-written loop

While on a fuzzer-found test case (added) that loop was faster,
on real fonts, including NotoNastaliq in our benchmark, it was
actually slower, which intuitively I would have expected.

Still no idea why on that fuzzer case it's faster though. :(

src/OT/Layout/Common/CoverageFormat2.hh

@@ -141,9 +141,6 @@ struct CoverageFormat2_4
   template <typename IterableOut,
 	    hb_requires (hb_is_sink_of (IterableOut, hb_codepoint_t))>
   void intersect_set (const hb_set_t &glyphs, IterableOut &intersect_glyphs) const
-  {
-    /* Why the second branch is >2x faster I have no idea, but it seems to be. */
-    if (0)
   {
     for (const auto& range : rangeRecord)
     {
@@ -153,28 +150,6 @@ struct CoverageFormat2_4
 	intersect_glyphs << g;
     }
   }
-    else
-    {
-      iter_t c_iter;
-      c_iter.init (*this);
-      auto s_iter = hb_iter (glyphs);
-      while (c_iter.__more__ () && s_iter)
-      {
-	hb_codepoint_t cv = c_iter.get_glyph ();
-	hb_codepoint_t sv = *s_iter;
-	if (cv == sv)
-	{
-	  intersect_glyphs << cv;
-	  c_iter.__next__ ();
-	  s_iter++;
-	}
-	else if (cv < sv)
-	  c_iter.__next__ ();
-	else
-	  s_iter++;
-      }
-    }
-  }
 
   template <typename set_t>
   bool collect_coverage (set_t *glyphs) const