Faster promesa.exec/wrap-bindings

[alexandergunnarson]

83x faster than current implementation, per benchmarks:

(run-benchmark ; run on a single pinned core for clean test purposes
  (fn []
    (testing "`promesa.exec.csp` implementation"
      ;; 4.956172 µs — this is due to `promesa.exec/wrap-bindings`'s way of forwarding
      ;; bindings, which is 83x slower than `clojure.core/binding-conveyor-fn`
      (criterium/bench
        (csp/go))
    (testing "Bare implementation"
      ;; 59.033042 ns
      (criterium/bench
        (-> (Thread/ofVirtual)
            (.unstarted (fn []))
            (.start))))
    (testing "With `clojure.core/binding-conveyor-fn` bindings forwarding"
      ;; 58.851215 ns
      (criterium/bench
        (-> (Thread/ofVirtual)
            (.unstarted (binding-conveyor-fn (^{:once true} fn* [])))
            (.start))))))