Add a new API getExecutableMethodFileOffsets

This new API overloads the existing API of the same name and accepts
"Executable" as the argument type (rather than "Method" for the existing
one). This allows it to handle things like a constructor. The API reuses
the existing implementation which already handles an Executable
properly.

Bug: 400457896
Test: TH
Change-Id: I754e798da5b041edc3f9dcfe4a3476fea2a234bf