test: Suppress "parse failed" message in Batch tests (#6207)

The word `failed` in the test case makes it hard to search through the test logs when an actual test failure occurs, so this change renames the word to just `fail` instead.

src/test/app/Batch_test.cpp

@@ -427,6 +427,7 @@ class Batch_test : public beast::unit_test::suite
             auto const batchFee = batch::calcBatchFee(env, 0, 2);
             auto tx1 = batch::inner(pay(alice, bob, XRP(1)), seq + 1);
             tx1[jss::Fee] = "1.5";
+            env.set_parse_failure_expected(true);
             try
             {
                 env(batch::outer(alice, seq, batchFee, tfAllOrNothing),
@@ -438,6 +439,7 @@ class Batch_test : public beast::unit_test::suite
             {
                 BEAST_EXPECT(true);
             }
+            env.set_parse_failure_expected(false);
         }
 
         // temSEQ_AND_TICKET: Batch: inner txn cannot have both Sequence

src/test/app/Vault_test.cpp

@@ -2076,7 +2076,7 @@ class Vault_test : public beast::unit_test::suite
                 PrettyAsset const& asset,
                 Vault& vault,
                 MPTTester& mptt) {
-                testcase("MPT failed reserve to re-create MPToken");
+                testcase("MPT fail reserve to re-create MPToken");
 
                 auto [tx, keylet] =
                     vault.create({.owner = owner, .asset = asset});