Extend analysis-stats a bit

This adds some tools helpful when debugging nondeterminism in analysis-stats:
 - a `--randomize` option that analyses everything in random order
 - a `-vv` option that prints even more detail

Also add a debug log if Chalk fuel is exhausted (which would be a source of
nondeterminism, but didn't happen in my tests).

I found one source of nondeterminism (rust-lang/chalk#331), but there are still
other cases remaining.

crates/ra_hir_ty/src/traits.rs

@@ -60,6 +60,9 @@ impl TraitSolver {
                     context.0.db.check_canceled();
                     let remaining = fuel.get();
                     fuel.set(remaining - 1);
+                    if remaining == 0 {
+                        log::debug!("fuel exhausted");
+                    }
                     remaining > 0
                 })
             }