fix [2170898] abort() doesn't print a stack tarce

the issue here is that abort() can be called from anywhere, in particular
from malloc or free. When we try to use the debug_log functions, these
can end up calling into some code (like malloc/free) that called abort()
in the first place and end up in an infinite recursion loop.
diff --git a/libc/unistd/abort.c b/libc/unistd/abort.c
index d4e40e1..f323941 100644
--- a/libc/unistd/abort.c
+++ b/libc/unistd/abort.c
@@ -73,10 +73,8 @@
 	}
 
     /* temporary, for bug hunting */
-    debug_log("abort() called in pid %d\n", getpid());
     /* seg fault seems to produce better debuggerd results than SIGABRT */
     *((char*)0xdeadbaad) = 39;
-    debug_log("somehow we're not dead?\n");
     /* -- */
 
 	(void)kill(getpid(), SIGABRT);