Task Description: ResizablePMCArray (RPA) is one of the basic array-like types in Parrot. This type implements a particular behavior called nested autovivification. Nested autovivification is when we try to access a nested array that does not exist, and it is created automatically. This is not a behavior that we want out array types to implement. This issue is discussed in Parrot ticket #1561.

Remove the autovivification behavior from RPA.

Steps to Complete:

1. Create a fork of parrot/parrot on github
2. Modify src/pmc/resizablepmcarray.c to remove autovivification behavior (ask questions if you need help)
3. Write a test or tests to prove that the behavior is gone
4. Build parrot and run all tests
5. Update the ticket with your status
6. open a pull request on github.