Fix profile code (and possibly others) that call C functions to use "correct" macro

[andrewlow]

Looking at change a001954

It struck me that the code is making use of the Call() macro, but in fact it is calling an external C function. we may need to validate that it is always calling an external C function

As we work towards a more sane implementation of the ABI on Power, we may want to redirect some of these from Call() to CallCFunction().

[mtbrandy]

RegExpCEntryStub::Generate is another location to consider changing to use CallCFunction.