cutils: update property_get to use diagnose_if.

This lets us redeclare property_get with diagnose_if tagged on it,
so we no longer need to deal with overloads.

Bug: 12231437
Test: m checkbuild on bullhead aosp-master.
Change-Id: Ic55dcfeaa314f83d3713aabac7852cb766330fc8
1 file changed