[deps] Remove unnecessary zarith and piqirun deps in intermediate representation

lib/ir/dune

@@ -9,7 +9,7 @@
    ppx_deriving.iter
    ppx_deriving.fold))
  (inline_tests)
- (libraries base ocplib-endian piqirun.pb zarith ocamlgraph stdio))
+ (libraries base ocplib-endian ocamlgraph stdio))
 
 (env
  (dev