ext: move syscall wrappers from container

These are generally useful, and none of them are container-specific. Syscalls subtle to use and requiring container-specific setup remains in container.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/outcome/shim.go

@@ -159,7 +159,7 @@ func shimEntrypoint(k syscallDispatcher) {
 		logger.SetFlags(0)
 	}
 
-	if err := k.setDumpable(container.SUID_DUMP_DISABLE); err != nil {
+	if err := k.setDumpable(ext.SUID_DUMP_DISABLE); err != nil {
 		k.fatalf("cannot set SUID_DUMP_DISABLE: %v", err)
 	}