Update BankHashDetails to include EpochAccountsHash (#2466)

The EpochAccountsHash gets mixed into a Bank hash once an epoch. It is
just as important as the other items, and it was an oversight for the
field not to be included to BankHashDetails.

So, add EpochAccountsHash into BankHashDetails

runtime/src/bank/bank_hash_details.rs

@@ -121,6 +121,8 @@ pub struct BankHashComponents {
     pub accounts_delta_hash: String,
     pub signature_count: u64,
     pub last_blockhash: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub epoch_accounts_hash: Option<String>,
     pub accounts: AccountsDetails,
 }
 
@@ -149,6 +151,10 @@ impl SlotDetails {
                 accounts_delta_hash: accounts_delta_hash.to_string(),
                 signature_count: bank.signature_count(),
                 last_blockhash: bank.last_blockhash().to_string(),
+                // The bank is already frozen so this should not have to wait
+                epoch_accounts_hash: bank
+                    .wait_get_epoch_accounts_hash()
+                    .map(|hash| hash.as_ref().to_string()),
                 accounts: AccountsDetails { accounts },
             })
         } else {
@@ -327,6 +333,11 @@ pub mod tests {
                         accounts_delta_hash: "accounts_delta_hash".into(),
                         signature_count: slot + 10,
                         last_blockhash: "last_blockhash".into(),
+                        epoch_accounts_hash: if slot % 2 == 0 {
+                            Some("epoch_accounts_hash".into())
+                        } else {
+                            None
+                        },
                         accounts,
                     }),
                     transactions: vec![],