[OpenMP][FIX] Properly track and lookup Execution Domains

[OpenMP][FIX] Properly track and lookup Execution Domains

This is a two part fix. First, we need two Execution Domains (ED) to
track the values of a function. One for incoming values and one for
outgoing values. This was conflated before. Second, at the function
entry we need to look at the incoming information from call sites not
iterate over non-existing predecessors.