Revert "tweak NOT_REACHED in DEBUGGING builds"

This reverts commit 5b48e25f83f62f48ea280c49b00302e063384348.

The above commit breaks win32 builds:

    IO.xs(73) : error C2065: 'my_perl' : undeclared identifier
    IO.xs(73) : error C2223: left of '->IProc' must point to struct/union

where dist/IO/IO.xs contains:

    69: static int
    70: not_here(const char *s)
    71: {
    72:     croak("%s not implemented on this architecture", s);
    73:     NORETURN_FUNCTION_END;
    74: }

and perl.h contains:

    #  define NORETURN_FUNCTION_END NOT_REACHED;

1 files changed, 1 insertions, 2 deletions

diff --git a/perl.h b/perl.h
index a2ba5cdae0..c60aeef377 100644
--- a/perl.h
+++ b/perl.h
@@ -3744,12 +3744,11 @@ int perl_tsa_mutex_unlock(perl_mutex* mutex)
    so pass it through to C lib as a last resort */
 #    define ASSUME(x) assert(x)
 #  endif
-#  define NOT_REACHED ASSUME(0)
 #else
 #  define ASSUME(x) assert(x)
-#  define NOT_REACHED abort()
 #endif
 
+#define NOT_REACHED ASSUME(0)
 
 /* Some unistd.h's give a prototype for pause() even though
    HAS_PAUSE ends up undefined.  This causes the #define