Return the accounts data len delta after processing messages (#22986)

runtime/src/message_processor.rs

@@ -38,8 +38,8 @@ impl ::solana_frozen_abi::abi_example::AbiExample for MessageProcessor {
 /// Resultant information gathered from calling process_message()
 #[derive(Debug, Default, Clone, Copy, PartialEq, Eq)]
 pub struct ProcessedMessageInfo {
-    /// The new accounts data len
-    pub accounts_data_len: u64,
+    /// The change in accounts data len
+    pub accounts_data_len_delta: i64,
 }
 
 impl MessageProcessor {
@@ -149,7 +149,7 @@ impl MessageProcessor {
                 .map_err(|err| TransactionError::InstructionError(instruction_index as u8, err))?;
         }
         Ok(ProcessedMessageInfo {
-            accounts_data_len: invoke_context.get_accounts_data_meter().current(),
+            accounts_data_len_delta: invoke_context.get_accounts_data_meter().delta(),
         })
     }
 }