Move bank benchmark outside src

This will make it available to third party benchmarking tools.

benches/bank.rs

@@ -0,0 +1,51 @@
+#![feature(test)]
+
+extern crate bincode;
+extern crate rayon;
+extern crate solana;
+extern crate test;
+
+use bincode::serialize;
+use rayon::prelude::*;
+use solana::bank::*;
+use solana::hash::hash;
+use solana::mint::Mint;
+use solana::signature::{KeyPair, KeyPairUtil};
+use solana::transaction::Transaction;
+use test::Bencher;
+
+#[bench]
+fn bench_process_transaction(bencher: &mut Bencher) {
+    let mint = Mint::new(100_000_000);
+    let bank = Bank::new(&mint);
+
+    // Create transactions between unrelated parties.
+    let transactions: Vec<_> = (0..4096)
+        .into_par_iter()
+        .map(|i| {
+            // Seed the 'from' account.
+            let rando0 = KeyPair::new();
+            let tx = Transaction::new(&mint.keypair(), rando0.pubkey(), 10_000, mint.last_id());
+            assert!(bank.process_transaction(&tx).is_ok());
+
+            // Seed the 'to' account and a cell for its signature.
+            let last_id = hash(&serialize(&i).unwrap()); // Unique hash
+            bank.register_entry_id(&last_id);
+
+            let rando1 = KeyPair::new();
+            let tx = Transaction::new(&rando0, rando1.pubkey(), 1, last_id);
+            assert!(bank.process_transaction(&tx.clone()).is_ok());
+
+            // Finally, return a the transaction to benchmark.
+            tx
+        })
+        .collect();
+
+    bencher.iter(|| {
+        // Since benchmarker runs this multiple times, we need to clear the signatures.
+        bank.clear_signatures();
+
+        let results = bank.process_transactions(transactions.clone());
+        assert!(results.iter().all(Result::is_ok));
+    });
+}