Update filesystem permissions for task tracepoints.

These tracepoints are used for memory debugging, and should be enabled
for user builds.

Bug: 123367055
Test: manual: took a trace with Traceur and verified that these
tracepoints appear.

Change-Id: I31fafc11d60a96f2a4c58f2670decb2480c0ec78
Merged-In: I31fafc11d60a96f2a4c58f2670decb2480c0ec78