Allow pointers to one past the end of allocations

[langston-barrett]

No description provided.

[langston-barrett]

I've modified this PR so that it addresses #524 as well (since that's an issue about the same bit of code). Unfortunately, I'm running into a very strange message on the example included in that issue:

[18:19:55.182] "crucible_llvm_verify" (/home/siddharthist/code/tmp/range-2/test.saw:12:1-12:21):
at /home/siddharthist/code/tmp/range-2/test.saw:12:1
could not match specified value with actual value:
  actual (simulator) value: concrete pointer: allocation = 5, offset = 10
  specified value:          concrete pointer: allocation = 5, offset = 10
  type of actual value:    i8*
  type of specified value: i8*

This looks like it is probably because of a missing case in matchArg.