Compress the module executor's paths

The executor shrinks from 49.8 to 42.2 KB of -O2 text (module.c 34.0 to
27.0 KB) with the module format and API unchanged:

- The verifier reads its rules from the signature table: what each
  opcode's argument names, and which text or list it works on. Cursor and
  index operands must belong to that text or list and so does a pushed one;
  other values belong to nothing, so a value that merely came from a text no
  longer blocks a join. The loader and verifier fail through one path.
- The interpreter advances as it fetches and leaves through two exits: a
  stated fault, or a change the data refused.
- Key, text and message events take one path; a message brings its base
  revision and key. Starting an app opens its module over none, the path
  replacing takes, so every new state starts from its stored value.
- Paths that run once per module or app are marked cold and built for size;
  event paths stay built for speed (small GETs: 128k/s, as before).

0 files changed, 0 insertions, 0 deletions