simpleperf_writer_fuzzer: Bug Fix

Resolved heap-user-after-free crash which was triggered by
trying to free memory pointed by 'unique_ptr<Dso>' which was
already freed in destructor of Dso class.

Bug: 335562493
Test: ./simpleperf_writer_fuzzer

Change-Id: Ia94f711f73b84838d78bd791f71afbffc3373ff3
1 file changed