Infinite loop parsing upstream annotations proposal

[alexcrichton]

When wast2json is run on the upstream annotations proposal test it currently infinite loops:

$ wast2json testsuite/proposals/annotations/annotations.wast --enable-all
<hangs>

I've minimized this to:

(module quote "(@a \0a)")  ;; \n

where wast2json run over that file infinite loops.

[binji]

Thanks for reporting! I'll take a look.