rts: Fix -hT option with profiling rts

In dumpCensus we switch/case on doHeapProfile twice. The second switch
tries to barf on unknown doHeapProfile modes but HEAP_BY_CLOSURE_TYPE is
checked by the first switch and not included in the second.

So when trying to pass -hT to the profiling rts it barfs.

This commit simply merges the two switches into one which fixes this
problem.