[Gradle] Fix warnings in KotlinJsTest

^KT-56904 In Progress

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/KotlinJsTest.kt

@@ -6,7 +6,6 @@
 package org.jetbrains.kotlin.gradle.targets.js.testing
 
 import org.gradle.api.Action
-import org.gradle.api.DomainObjectSet
 import org.gradle.api.file.FileCollection
 import org.gradle.api.file.RegularFileProperty
 import org.gradle.api.tasks.*
@@ -21,6 +20,7 @@ import org.jetbrains.kotlin.gradle.targets.js.npm.RequiresNpmDependencies
 import org.jetbrains.kotlin.gradle.targets.js.testing.karma.KotlinKarma
 import org.jetbrains.kotlin.gradle.targets.js.testing.mocha.KotlinMocha
 import org.jetbrains.kotlin.gradle.tasks.KotlinTest
+import org.jetbrains.kotlin.gradle.utils.domainObjectSet
 import org.jetbrains.kotlin.gradle.utils.getFile
 import org.jetbrains.kotlin.gradle.utils.getValue
 import org.jetbrains.kotlin.gradle.utils.newFileProperty
@@ -48,14 +48,13 @@ constructor(
         set(value) {
             field = value
             onTestFrameworkCallbacks.all { callback ->
-                callback.execute(value)
+                value?.let { callback.execute(it) }
             }
         }
 
-    private var onTestFrameworkCallbacks: DomainObjectSet<Action<KotlinJsTestFramework?>> =
-        project.objects.domainObjectSet(Action::class.java) as DomainObjectSet<Action<KotlinJsTestFramework?>>
+    private var onTestFrameworkCallbacks = project.objects.domainObjectSet<Action<KotlinJsTestFramework>>()
 
-    fun onTestFrameworkSet(action: Action<KotlinJsTestFramework?>) {
+    fun onTestFrameworkSet(action: Action<KotlinJsTestFramework>) {
         onTestFrameworkCallbacks.add(action)
     }
 
@@ -94,7 +93,7 @@ constructor(
     val compilationId: String by lazy {
         compilation.let {
             val target = it.target
-            target.project.path + "@" + target.name + ":" + it.compilationPurpose
+            target.project.path + "@" + target.name + ":" + it.compilationName
         }
     }