add borrows to NLL MIR dumps

explicitly disable `-Zmir-include-spans` in mir-opt tests

This will override the NLL default of true, and keep the blessed dumps
easier to work with.

compiler/rustc_borrowck/src/lib.rs

@@ -229,7 +229,7 @@ fn do_mir_borrowck<'tcx>(
 
     // Dump MIR results into a file, if that is enabled. This let us
     // write unit-tests, as well as helping with debugging.
-    nll::dump_nll_mir(&infcx, body, &regioncx, &opt_closure_req);
+    nll::dump_nll_mir(&infcx, body, &regioncx, &opt_closure_req, &borrow_set);
 
     // We also have a `#[rustc_regions]` annotation that causes us to dump
     // information.