Use re-calibrated costs for loadgen. (#4601)

# Description

Use re-calibrated costs for loadgen.

Also update the `generate soroban load` test to not use the config for
genesis and go through the protocol upgrade instead, so that it
resembles the supercluster missions closer.

# Checklist
- [ ] Reviewed the
[contributing](https://github.com/stellar/stellar-core/blob/master/CONTRIBUTING.md#submitting-changes)
document
- [ ] Rebased on top of master (no merge commits)
- [ ] Ran `clang-format` v8.0.0 (via `make format` or the Visual Studio
extension)
- [ ] Compiles
- [ ] Ran all tests
- [ ] If change impacts performance, include supporting evidence per the
[performance
document](https://github.com/stellar/stellar-core/blob/master/performance-eval/performance-eval.md)

src/herder/Upgrades.cpp

@@ -1199,6 +1199,16 @@ Upgrades::applyVersionUpgrade(Application& app, AbstractLedgerTxn& ltx,
     if (needUpgradeToVersion(SOROBAN_PROTOCOL_VERSION, prevVersion, newVersion))
     {
         SorobanNetworkConfig::createLedgerEntriesForV20(ltx, app);
+#ifdef BUILD_TESTS
+        // Update the costs in case if we're in loadgen mode, so that the costs
+        // reflect the most recent calibration on p20. This would break
+        // if we tried to replay the ledger, but we shouldn't be combining load
+        // generation with the ledger replay.
+        if (app.getConfig().ARTIFICIALLY_GENERATE_LOAD_FOR_TESTING)
+        {
+            SorobanNetworkConfig::updateRecalibratedCostTypesForV20(ltx);
+        }
+#endif
     }
     if (needUpgradeToVersion(ProtocolVersion::V_21, prevVersion, newVersion))
     {

src/simulation/test/LoadGeneratorTests.cpp

@@ -197,8 +197,9 @@ TEST_CASE("generate soroban load", "[loadgen][soroban]")
     Simulation::pointer simulation =
         Topologies::pair(Simulation::OVER_LOOPBACK, networkID, [&](int i) {
             auto cfg = getTestConfig(i);
-            cfg.TESTING_UPGRADE_MAX_TX_SET_SIZE = 5000;
-            // Use tight bounds to we can verify storage works properly
+            cfg.USE_CONFIG_FOR_GENESIS = false;
+            cfg.ARTIFICIALLY_GENERATE_LOAD_FOR_TESTING = true;
+            //  Use tight bounds to we can verify storage works properly
             cfg.LOADGEN_NUM_DATA_ENTRIES_FOR_TESTING = {numDataEntries};
             cfg.LOADGEN_NUM_DATA_ENTRIES_DISTRIBUTION_FOR_TESTING = {1};
             cfg.LOADGEN_IO_KILOBYTES_FOR_TESTING = {ioKiloBytes};
@@ -220,6 +221,20 @@ TEST_CASE("generate soroban load", "[loadgen][soroban]")
     auto nodes = simulation->getNodes();
 
     auto& app = *nodes[0]; // pick a node to generate load
+    Upgrades::UpgradeParameters scheduledUpgrades;
+    auto lclCloseTime =
+        VirtualClock::from_time_t(app.getLedgerManager()
+                                      .getLastClosedLedgerHeader()
+                                      .header.scpValue.closeTime);
+    scheduledUpgrades.mUpgradeTime = lclCloseTime;
+    scheduledUpgrades.mProtocolVersion =
+        Config::CURRENT_LEDGER_PROTOCOL_VERSION;
+    for (auto const& node : nodes)
+    {
+        node->getHerder().setUpgrades(scheduledUpgrades);
+    }
+    simulation->crankForAtLeast(std::chrono::seconds(20), false);
+
     auto& loadGen = app.getLoadGenerator();
     auto getSuccessfulTxCount = [&]() {
         return nodes[0]