rustc: Use the generic info from the item in bind thunks just as calls do. Un-XFAIL drop-parametric-closure-with-bound-box.rs.

src/Makefile

@@ -448,7 +448,6 @@ TEST_XFAILS_RUSTC := $(addprefix test/run-pass/, \
                         comm.rs \
                         constrained-type.rs \
                         destructor-ordering.rs \
-                        drop-parametric-closure-with-bound-box.rs \
                         foreach-nested-2.rs \
                         foreach-nested.rs \
                         foreach-put-structured.rs \

src/comp/middle/trans.rs

@@ -3750,6 +3750,8 @@ fn trans_bind(@block_ctxt cx, @ast.expr f,
                         bcx.build.Store(td, ty_param_slot);
                         i += 1;
                     }
+
+                    outgoing_fty = ginfo.item_type;
                 }
             }