Fixed standalone test build.

.travis.yml

@@ -1,6 +1,6 @@
 language: java
 jdk:
-  - openjdk17
+  - openjdk11
 
 before_script:
   - chmod +x gradlew

build.gradle

@@ -28,6 +28,7 @@ dependencies {
     testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.9.0'
     testImplementation "org.jetbrains.kotlin:kotlin-test"
     testImplementation "org.jetbrains.kotlin:kotlin-reflect"
+    testImplementation 'org.junit.platform:junit-platform-launcher:1.9.0'
 //    testImplementation "org.jetbrains.kotlin:kotlin-test-junit"
 }
 
@@ -72,10 +73,6 @@ test {
     }
 }
 
-tasks.test {
-    systemProperty("idea.force.use.core.classloader", "true")
-}
-
 jacoco {
     toolVersion = '0.8.8'
 }