winio: fix heap corruption and various leaks.

libraries/base/GHC/Event/Windows.hsc

libraries/base/GHC/IO/Windows/Paths.hs

libraries/base/System/IO.hs

libraries/base/cbits/Win32Utils.c

rts/RtsStartup.c

rts/RtsSymbols.c

rts/include/rts/IOInterface.h

rts/win32/AsyncWinIO.c

rts/win32/ConsoleHandler.c

rts/win32/ConsoleHandler.h

rts/win32/ThrIOManager.c

rts/win32/ThrIOManager.h