Add a new "v8_perf_prof_unwinding_info" option to gn that translates to building
the snapshot with "--perf-prof-unwinding-info". It allows unwinding TF generated
code from the snapshot.

Additionally, add a warning if one uses the option along with a snapshot which
was not build with unwinding information.

Running tests in this configuration revealed an issue in the checks performed
when accessing the stub cache. We would assume that the `Code::Flags` bitfield
only contains the `Kind` and `ExtraICState` fields, when there is also a
`HasUnwindingInfo` field which can now be set for stubs.

BUG=

Review-Url: https://codereview.chromium.org/2887783002
Cr-Commit-Position: refs/heads/master@{#45477}