Bug#37689487 - JIT tests in router suite must be skippable

Description
===========
MySQL REST Service in router introduced new plugin jit_executor.so,
which builds only when cmake was configured with external jit-executor:

    cmake -DMRS_JIT_EXECUTOR_LIB=/export/mysql/libs/jit-executor-commercial-23.0.1-ubuntu24.04-x86-64bit/ .

This results in placing jit-executor.so is inside router plugin directory,
and router can load it.

Fix
===
Added "have_jit_executor.inc", which can be used by router tests that
loads "jit-executor".

(POST-PUSH FIX WL#15440)

Change-Id: I84b1d0af0bd2a1c83eeb303b556512425e9b5b1d

Author: lkotula

mysql-test/include/have_jit_executor.inc

@@ -0,0 +1,5 @@
+# Should be used by the Router test when it uses jit_executor plugin.
+# The plugin is build only when cmake was configurated with:
+#
+#    -DMRS_JIT_EXECUTOR_LIB=...
+#

mysql-test/lib/mtr_cases.pm

@@ -1565,9 +1565,34 @@ sub collect_one_test_case {
       skip_test($tinfo, "No router executable available.");
       return $tinfo;
     }
+
+    if ($::plugin_mysqlrouter_routing eq "") {
+      # Packaging problem, must be deployed with MySQLRouter
+      skip_test($tinfo, "No routing plugin available.");
+      return $tinfo;
+    }
   }
   $router_test = 1 if ($tinfo->{'router_test'});
 
+  # Check for router-jit-executor tests
+  if ($tinfo->{'router_jit_executor_test'}) {
+    # check if the router executable was found (built)
+    if ($::plugin_mysqlrouter_jit_executor eq "") {
+      skip_test($tinfo, "No jit_executor plugin available.");
+      return $tinfo;
+    }
+  }
+
+  # Check for MySQL Router bootstrap tests
+  if ($tinfo->{'router_bootstrap_test'}) {
+    # check if the routing plugin was found (built)
+    if ($::plugin_mysqlrouter_routing eq "") {
+      # Packaging problem, must be deployed with MySQLRouter
+      skip_test($tinfo, "No routing plugin available.");
+      return $tinfo;
+    }
+  }
+
   if ($tinfo->{'not_windows'} && IS_WINDOWS) {
     skip_test($tinfo, "Test not supported on Windows");
     return $tinfo;
@@ -1706,7 +1731,10 @@ my @tags = (
 
   [ "include/not_asan.inc", "not_asan", 1 ],
   [ "include/not_ubsan.inc", "not_ubsan", 1 ],
+
+  # Tests with below .inc files are considered to be MySQL Router tests.
   [ "have_router.inc",      "router_test", 1 ],
+  [ "have_jit_executor.inc",      "router_jit_executor_test", 1 ],
   [ "have_router_bootstrap.inc",  "router_bootstrap_test", 1 ],
 
   # Tests with below .inc file needs either big-test or only-big-test

mysql-test/mysql-test-run.pl

@@ -366,6 +366,8 @@
 our $exe_mysqlrouter;
 our $exe_mysqlrouter_mrs_client;
 our $exe_mysqlrouter_keyring;
+our $plugin_mysqlrouter_jit_executor;
+our $plugin_mysqlrouter_routing;
 
 our $glob_debugger       = 0;
 our $group_replication   = 0;
@@ -2987,6 +2989,9 @@ ()
     my_find_bin($bindir,
               [ "runtime_output_directory", "libexec", "sbin", "bin" ],
               "mysqlrouter_mrs_client", NOT_REQUIRED);
+
+  $plugin_mysqlrouter_jit_executor = find_router_plugin("jit_executor");
+  $plugin_mysqlrouter_routing = find_router_plugin("routing");
 }
 
 sub client_debug_arg($$) {
@@ -3187,6 +3192,16 @@ ($)
                          "$basedir/lib/" . $plugin_filename);
 }
 
+sub find_router_plugin($) {
+  my ($plugin) = @_;
+  my $router_plugin = find_plugin($plugin, "plugin_output_directory");
+  if (!$router_plugin) {
+    $router_plugin = find_router_plugin_in_package($plugin);
+  }
+  return $router_plugin;
+}
+
+
 # Read plugin defintions file
 sub read_plugin_defs($$) {
   my ($defs_file, $remove_config) = @_;
@@ -5268,11 +5283,7 @@ ($)
     if (!$tinfo->{router_test}) {
       $config_router = ();
       if ($tinfo->{router_bootstrap_test}) {
-        my $routing_plugin = find_plugin("routing", "plugin_output_directory");
-        if (!$routing_plugin) {
-          $routing_plugin = find_router_plugin_in_package("routing") or die();
-        }
-        my $plugin_dir = dirname($routing_plugin);
+        my $plugin_dir = dirname($plugin_mysqlrouter_routing);
         $ENV{"ROUTER_PLUGIN_DIRECTORY"} = $plugin_dir;
       }
     }