port 3a9152ec (r42594)

  original commit message:
  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.

BUG=

Review-Url: https://codereview.chromium.org/2649893004
Cr-Commit-Position: refs/heads/master@{#42617}