flambda-backend: Move compiler_float32 code into flambda2 (#2511)

move f32 lib to fl2

Author: TheNumbat

Makefile.common-jst

@@ -271,8 +271,6 @@ install_for_test: _install
 	# Various directories are put on the -I paths by tools/Makefile;
 	# utils/ is one such, so we just dump the .cm* files in there for
 	# various things.
-	mkdir _runtest/external
-	cp $(main_build)/external/float32/*.{cma,a,cmxa} _runtest/external
 	mkdir _runtest/utils
 	cp _install/lib/ocaml/compiler-libs/*.{cmi,cmx} _runtest/utils
 	cp $(main_build)/$(ocamldir)/.ocamlcommon.objs/byte/*.cmo _runtest/utils