Add support for the 'TicketBatch' amendment:

Support for 'out-of-sequence' transaction execution was introduced
in commit 7724cca384.

The changes in that commit were gated under a feature but there was
no corresponding amendment introduced that would allow the network
to vote on this amendment.

This commit introduces 'TicketBatch' amendment as the amendment
that is associated with the tickets feature. If the amendment is
enabled, it will activate support for tickets.

This commit also removes several workarounds that are no longer
needed in unit tests.

src/test/rpc/AccountObjects_test.cpp

@@ -346,7 +346,7 @@ public:
         Account const gw{"gateway"};
         auto const USD = gw["USD"];
 
-        Env env(*this, supported_amendments() | featureTicketBatch);
+        Env env(*this);
 
         // Make a lambda we can use to get "account_objects" easily.
         auto acct_objs = [&env](Account const& acct, char const* type) {

src/test/rpc/AccountSet_test.cpp

@@ -507,7 +507,7 @@ public:
     testTicket()
     {
         using namespace test::jtx;
-        Env env(*this, supported_amendments() | featureTicketBatch);
+        Env env(*this);
         Account const alice("alice");
 
         env.fund(XRP(10000), alice);

src/test/rpc/AccountTx_test.cpp

@@ -252,7 +252,7 @@ class AccountTx_test : public beast::unit_test::suite
         using namespace test::jtx;
         using namespace std::chrono_literals;
 
-        Env env(*this, supported_amendments() | featureTicketBatch);
+        Env env(*this);
         Account const alice{"alice"};
         Account const alie{"alie"};
         Account const gw{"gw"};

src/test/rpc/LedgerData_test.cpp

@@ -18,7 +18,6 @@
 //==============================================================================
 
 #include <ripple/basics/StringUtilities.h>
-#include <ripple/protocol/Feature.h>
 #include <ripple/protocol/jss.h>
 #include <test/jtx.h>
 
@@ -309,10 +308,7 @@ public:
         // Put a bunch of different LedgerEntryTypes into a ledger
         using namespace test::jtx;
         using namespace std::chrono;
-        Env env{
-            *this,
-            envconfig(validator, ""),
-            supported_amendments() | featureTicketBatch};
+        Env env{*this, envconfig(validator, "")};
 
         Account const gw{"gateway"};
         auto const USD = gw["USD"];

src/test/rpc/LedgerRPC_test.cpp

@@ -22,7 +22,6 @@
 #include <ripple/basics/StringUtilities.h>
 #include <ripple/beast/unit_test.h>
 #include <ripple/protocol/ErrorCodes.h>
-#include <ripple/protocol/Feature.h>
 #include <ripple/protocol/jss.h>
 #include <test/jtx.h>
 
@@ -1107,7 +1106,7 @@ class LedgerRPC_test : public beast::unit_test::suite
     {
         testcase("ledger_entry Request Ticket");
         using namespace test::jtx;
-        Env env{*this, supported_amendments() | featureTicketBatch};
+        Env env{*this};
         env.close();
 
         // Create two tickets.