Revert "TEMP: destroy the way profiling deals with scc statements"

This reverts commit 263661cb8a2694d82b706877d20207363dea71ee.
Add -scc-trace flag, and a new file compiler/codeGen/StgCmmCostCentreStackTrace.hs, which
is a haskell wrapper around rts/CostCentreStackTrace.c