Revert "mediaextractor: ignore platform's profiler assist signal"

This reverts commit 0c3505bf.

Reason for revert: aosp/1242758 protects against sigsys-based seccomp
crashes from within the profiling signal handler. This should make the
mediaextractor-specific disabling of the profiling handler unnecessary.

Test: sent profiling signal to mediaextractor, observed logging
      that confirmed that the sendmsg() violation was recovered-from.
Bug: 149328505
Change-Id: I70a3bf94584cecf398f6b66161a2c0583e841070