This change allows to save:
- some memory by removing the method name from CallStat and CallSession
- some CPU by not calling binder.resolveCode for every binder call
at the expense of some hackiness (calling getDefaultTransactionCode
using reflection)
BinderCallsStats#getExportedCallsStats is now more costly to call but it
will be invoked only once a day only.
Test: unit test
Change-Id: Id4f933644c6da9d4aa2d0671db4ab80676eac1b0
1f93a77b5c