Motivated by finding a bug in a larger module, this CL adds the ability
to dump out a byte-by-byte, nested view of the decoded AST. This
byte-by-byte output uses the opcode enum to make it readable, but is
suitable for pasting into a byte[] in C or JS and thus making a regression
test.

Also fix a bug; the case of running out of registers for indirect calls.

R=ahaas@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1616973004

Cr-Commit-Position: refs/heads/master@{#33442}