Debugger: Fix interrupting code.

- Windows: Always use DebugBreakProcess if Qt Creator is compiled
  64bit. Else always use win64interrupt.exe if Qt Creator
  is a WOW64 application.
- Remove redundant code (procinterrupt/hostutils, gdb adapters).
- Give interruptProcess an errorMessage parameter such that it can
  be used by all C++ engines and a proper error is displayed.
- Improve error messages.
- Build win64interrupt if target architecture is 64 bit (clean tools
  profile, add a profile), borrowing the check from
  qtcreatorcdbext.pro.

Change-Id: I2a6caf98e46051c49c84e1f3aac4c8d2aba66e8b
Reviewed-by: David Schulz <david.schulz@nokia.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@nokia.com>