1098eafb45
WebAssembly doesn't have non-dense jump tables, and higher-level users are better served by the facilities in lib/frontend/src/switch.rs for working with non-dense switches. This eliminates the concept of "absent" jump table entries, which were represented as "0" in the text format. Also, jump table contents are now enclosed in `[` and `]`, so that we can unambiguously display empty jump tables. Previously, empty jump tables were displayed as if they had a single absent entry.