We are planning to add a few more debugger related bits, and are running
out of compiler hints bits. The new bit field is going to be part of the
debug info struct. If the debug info is not available, we store the bit
field in its place on the shared function info.

Review-Url: https://codereview.chromium.org/2649873002
Cr-Commit-Position: refs/heads/master@{#42594}