Stack sampling profiler: retry re-enable at 15%
Stack sampling profiler: retry re-enable at 15%

First step in a gradual re-enabling of the profiler using the new
stack copying approach. Trying again after addressing crashes unwinding
through unloaded modules.

BUG=541419

Review URL: https://codereview.chromium.org/1415103007

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#357973}

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