read: improve handling of 0 for tombstones #542

Job	Run time
msrv	3m 2s
Build fuzz targets	1m 7s
bench	1m 0s
cross (i686-unknown-linux-gnu)	42s
build (ubuntu-latest, stable)	41s
features	3m 0s
cross (powerpc64-unknown-linux-gnu)	49s
build (ubuntu-latest, beta)	47s
msrv-read	2m 56s
build (ubuntu-latest, nightly)	41s
rustfmt	5s
build (stable, macOS-latest)	40s
coverage	1m 6s
doc	18s
Run `debug_abbrev` fuzz target	5m 8s
Run `debug_aranges` fuzz target	5m 7s
Run `debug_info` fuzz target	5m 11s
Run `debug_line` fuzz target	5m 6s
Run `eh_frame` fuzz target	5m 10s
Run `eh_frame_hdr` fuzz target	5m 7s
	47m 43s

Provide feedback