Fix flaky hashes_to_transactions tests (non-ordered results)

apps/explorer/lib/explorer/chain.ex

@@ -587,9 +587,9 @@ defmodule Explorer.Chain do
       iex> [%Transaction{hash: hash1}, %Transaction{hash: hash2}] = insert_list(2, :transaction)
       iex> [%Explorer.Chain.Transaction{hash: found_hash1}, %Explorer.Chain.Transaction{hash: found_hash2}] =
       ...>   Explorer.Chain.hashes_to_transactions([hash1, hash2])
-      iex> found_hash1 == hash1
+      iex> found_hash1 in [hash1, hash2]
       true
-      iex> found_hash2 == hash2
+      iex> found_hash2 in [hash1, hash2]
       true
 
   Returns `[]` if not found

apps/explorer/test/explorer/chain_test.exs

@@ -529,11 +529,9 @@ defmodule Explorer.ChainTest do
                  necessity_by_association: %{block: :required}
                )
 
-      assert [%Transaction{hash: ^hash_without_index1}, %Transaction{hash: ^hash_without_index2}] =
-               Chain.hashes_to_transactions(
-                 [hash_without_index1, hash_without_index2],
-                 necessity_by_association: %{block: :optional}
-               )
+      assert [hash_without_index1, hash_without_index2]
+             |> Chain.hashes_to_transactions(necessity_by_association: %{block: :optional})
+             |> Enum.all?(&(&1.hash in [hash_without_index1, hash_without_index2]))
     end
   end