Removed all instances of crash_prog()

crash_prog was introduced to force-crash a userspace program
since _exit may not yet be implemented. However, the new versions
of OS161 already have the exact same logic as crash_prog in stdlib/exit.

userland/testbin/consoletest/consoletest.c

@@ -54,11 +54,5 @@ main(int argc, char **argv)
 	(void) argv;
 
 	secprintf(SECRET, "Able was i ere i saw elbA", "/testbin/consoletest");
-
-	// Guru: Since exit() may not yet be implemented, just trigger a
-	// failure that the grading scripts expect to see.
-	tprintf("Accessing invalid memory location to trigger failure\n");
-	tprintf("%d", *((int *) 0xd34db33f));
-
 	return 0;
 }