fd25f80a1 make it possible to disable debug symbols stripping (flutter/engine#11265) (#39291)

git@github.com:flutter/engine.git/compare/59e14bc5f69e...fd25f80a1d3c

git log 59e14bc5f69e..fd25f80a1d3c --no-merges --oneline
2019-08-26 xster@google.com make it possible to disable debug symbols stripping (flutter/engine#11265)


If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/flutter-engine-flutter-autoroll
Please CC liyuqian@google.com on the revert to ensure that a human
is aware of the problem.

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https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md