[truetype] Upstream the hdmx binary search.

* src/truetype/ttobjs.h (TT_SizeRec): Add `widthp` for the hdmx
widths.
* src/truetype/ttobjs.c (tt_size_reset): Initialize `widthp` even
though it might never be used by the interpreter.
* src/truetype/ttgload.c (tt_loader_init): Avoid repeated searches
in the hdmx table.
3 files changed