Exception when trying to invoke apply() method of control instantiated at top level

[jafingerhut]

I can instantiate a control A within control B, then invoke A.apply() within control B's apply block. However, if I change it to instantiate A at the top level, the compiler crashes. Not sure if this is intended to be a legal P4_16 program or not.

Look for occurrences of my_cBar in attached program.
method-call-on-top-level-control-inst.p4.txt

[mihaibudiu]

I think this is a duplicate of #388.
But this issue has a much better title.
Both of these are related to a spec issue: p4lang/p4-spec#150
So we can't fix this one until we settle the problem in the spec.