tests: Remove created test wallets when done.

src/wallet/cashierdb.rs

@@ -345,6 +345,7 @@ mod tests {
         assert_eq!(addr.is_none(), true);
 
         wallet.destroy()?;
+        std::fs::remove_file(walletdb_path)?;
 
         Ok(())
     }

src/wallet/walletdb.rs

@@ -311,6 +311,7 @@ mod tests {
         assert_eq!(secret, keypair.private);
 
         wallet.destroy()?;
+        std::fs::remove_file(walletdb_path)?;
 
         Ok(())
     }
@@ -360,6 +361,7 @@ mod tests {
         assert_eq!(own_coin.witness.path(), witness.path());
 
         wallet.destroy()?;
+        std::fs::remove_file(walletdb_path)?;
 
         Ok(())
     }
@@ -424,6 +426,7 @@ mod tests {
         }
 
         wallet.destroy()?;
+        std::fs::remove_file(walletdb_path)?;
 
         Ok(())
     }