NotoColorEmoji.ttf uses two cmap subtables
Format 14 | Platform ID 0 | Platform Encoding ID 5
Format 12 | Platform ID 3 | Platform Encoding ID 10
This combination results in the cmap table being dropped during subsetting despite being valid/required.
Include stdbool.h in hb-setset-test.h instead of in the individual
sources, if it is found; otherwise use a simplistic fallback for it if
it is not found.
Also declare variables at the top of the block, to build on pre-C99
compiliers.