If the source checkout had 'debug' somewhere in the path name, then
IsDebuggerFile() marked all modules as debug ones, which triggered
an assertion during snapshot generation.

Bug: 
Change-Id: I93537efca9152c5469bb760f32ca53b06351f7a4
Reviewed-on: https://chromium-review.googlesource.com/809205Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49980}