Remove MALLOC_CHECK and calls to it entirely

MALLOC_CHECK got useless with commit b259af5.  Remove it throughout.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

winsup/cygwin/fork.cc

@@ -174,8 +174,6 @@ frok::child (volatile char * volatile here)
     }
 #endif
 
-  MALLOC_CHECK;
-
   /* Incredible but true:  If we use sockets and SYSV IPC shared memory,
      there's a good chance that a duplicated socket in the child occupies
      memory which is needed to duplicate shared memory from the parent
@@ -186,8 +184,6 @@ frok::child (volatile char * volatile here)
   if (fixup_shms_after_fork ())
     api_fatal ("recreate_shm areas after fork failed");
 
-  MALLOC_CHECK;
-
   /* If we haven't dynamically loaded any dlls, just signal
      the parent.  Otherwise, load all the dlls, tell the parent
       that we're done, and wait for the parent to fill in the.
@@ -463,7 +459,6 @@ frok::parent (volatile char * volatile stack_here)
      Note: variables marked as NO_COPY will not be copied since they are
      placed in a protected segment.  */
 
-  MALLOC_CHECK;
   const void *impure_beg;
   const void *impure_end;
   const char *impure;
@@ -482,7 +477,6 @@ frok::parent (volatile char * volatile stack_here)
 
   __malloc_unlock ();
   locked = false;
-  MALLOC_CHECK;
   if (!rc)
     {
       this_errno = get_errno ();
@@ -622,7 +616,6 @@ fork ()
       }
   }
 
-  MALLOC_CHECK;
   if (ischild)
     {
       myself->process_state |= PID_ACTIVE;