Workaround 'variable reassigned before old value used' cppcheck warnings
* misc.c (GC_call_with_gc_active): Call GC_noop1 for
GC_traced_stack_sect and GC_blocked_sp (before restoring their original
values) if CPPCHECK.
* win32_threads.c (GC_do_blocking_inner): Call GC_noop1 for
thread_blocked_sp field (before restoring its original value)
if CPPCHECK.
* win32_threads.c (GC_call_with_gc_active): Call GC_noop1 for
traced_stack_sect field (before restoring its original value)
if CPPCHECK.