[test] t/dynoplibs/debug.t

skip debug_break only on windows.
test okay on darwin, cygwin, cygwin64 and linux.
pmc2c: inline gc write barrier into vtable methods

removed wrong UNUSED(INTERP) and UNUSED(SELF)
some methods with return values are marked TODO, need to add the write barriers manually.

A missing write barrier caused one error:
t/examples/shootout.t: 16 examples/shootout/regexdna.pir SEGV

TODO GC write barrier to:
default.pop_float
default.pop_integer
default.pop_pmc
default.pop_string
default.shift_float
default.shift_integer
default.shift_pmc
default.shift_string
CallContext.shift_pmc
CallContext.shift_string
Key.shift_pmc
ArrayIterator.pop_float
ArrayIterator.pop_integer
ArrayIterator.pop_pmc
ArrayIterator.pop_string
ArrayIterator.shift_float
ArrayIterator.shift_integer
ArrayIterator.shift_pmc
ArrayIterator.shift_string
Task.pop_pmc
Capture.pop_float
Capture.pop_integer
Capture.pop_pmc
Capture.pop_string
Capture.shift_float
Capture.shift_integer
Capture.shift_pmc
Capture.shift_string
HashIterator.shift_integer
HashIterator.shift_pmc
HashIterator.shift_string
ImageIOThaw.shift_float
ImageIOThaw.shift_integer
ImageIOThaw.shift_pmc
ImageIOThaw.shift_string
ResizablePMCArray.pop_float
ResizablePMCArray.pop_integer
ResizablePMCArray.pop_pmc
ResizablePMCArray.pop_string
ResizablePMCArray.shift_float
ResizablePMCArray.shift_integer
ResizablePMCArray.shift_pmc
ResizablePMCArray.shift_string
Object.pop_float
Object.pop_integer
Object.pop_pmc
Object.pop_string
Object.shift_float
Object.shift_integer
Object.shift_pmc
Object.shift_string
OrderedHashIterator.pop_pmc
OrderedHashIterator.shift_pmc
OrderedHashIterator.shift_string
PMCList.pop_pmc
PMCList.shift_pmc
ResizableBooleanArray.pop_integer
ResizableBooleanArray.shift_integer
ResizableFloatArray.pop_float
ResizableFloatArray.shift_float
ResizableIntegerArray.pop_integer
ResizableIntegerArray.shift_integer
ResizableStringArray.pop_float
ResizableStringArray.pop_integer
ResizableStringArray.pop_pmc
ResizableStringArray.pop_string
ResizableStringArray.shift_float
ResizableStringArray.shift_integer
ResizableStringArray.shift_pmc
ResizableStringArray.shift_string
Scheduler.shift_pmc
StringIterator.pop_integer
StringIterator.pop_pmc
StringIterator.pop_string
StringIterator.shift_integer
StringIterator.shift_pmc
StringIterator.shift_string