Rollup merge of #70368 - bjorn3:patch-2, r=jonas-schievink

Mark hotplug_codegen_backend as ignore-stage1

Suggested by @eddyb in https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/do.20we.20really.20need.20stage2.2E.2E.3F/near/191659846.

Author: Centril

src/test/run-make-fulldeps/hotplug_codegen_backend/Makefile

@@ -1,5 +1,7 @@
 include ../tools.mk
 
+# ignore-stage1
+
 all:
 	/bin/echo || exit 0 # This test requires /bin/echo to exist
 	$(RUSTC) the_backend.rs --crate-name the_backend --crate-type dylib \