rts: Print correct stack size on stack overflow

This requires that stackOverflow() in RtsUtils.c be passed a reference
to the current TSO. This requires a small change in libraries/base.
rts: Allow for infinite stack size

This is encoded as RtsFlags.GcFlags.maxStkSize == 0.
rts: Disable maximum stack size by default

This closes Ticket #8189.
rts/Constants.h: Remove outdated comment

I believe HeapOverflow now unambiguously indicates that the heap has
overflowed as stack allocation failure is now handled separatly.
rts: Fix typo in comment