The trace turbo output will overwrite itself when functions in different
files share the same name. Output files now have the form
`turbo-<function_name>:<opt_file_name>-<opt_phase>.suffix`.

R=ofrobots@google.com
BUG=

Review-Url: https://codereview.chromium.org/2083863004
Cr-Commit-Position: refs/heads/master@{#37199}