[Native][tests] Simplify condition in AbstractNativeBlackBoxTest.buildJUnitDynamicNodes()

native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/AbstractNativeBlackBoxTest.kt

@@ -10,6 +10,7 @@ import org.jetbrains.kotlin.konan.blackboxtest.support.*
 import org.jetbrains.kotlin.konan.blackboxtest.support.util.TreeNode
 import org.jetbrains.kotlin.konan.blackboxtest.support.util.getAbsoluteFile
 import org.jetbrains.kotlin.konan.blackboxtest.support.util.joinPackageNames
+import org.jetbrains.kotlin.konan.blackboxtest.support.util.prependPackageName
 import org.junit.jupiter.api.DynamicNode
 import org.junit.jupiter.api.DynamicTest.dynamicTest
 import org.junit.jupiter.api.extension.ExtendWith
@@ -71,10 +72,7 @@ abstract class AbstractNativeBlackBoxTest {
             fun TreeNode<TestRun>.processItems(parentPackageSegment: String) {
                 val ownPackageSegment = joinPackageNames(parentPackageSegment, packageSegment)
                 items.mapTo(this@buildList) { testRun ->
-                    val displayName = if (ownPackageSegment.isNotEmpty())
-                        "$ownPackageSegment.${testRun.displayName}"
-                    else
-                        testRun.displayName
+                    val displayName = testRun.displayName.prependPackageName(ownPackageSegment)
                     dynamicTest(displayName) { runTest(testRun) }
                 }
 

native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/support/util/PackageNames.kt

@@ -71,3 +71,6 @@ internal fun joinPackageNames(a: PackageFQN, b: PackageFQN): PackageFQN = when {
     b.isEmpty() -> a
     else -> "$a.$b"
 }
+
+internal fun String.prependPackageName(packageName: PackageFQN): String =
+    if (packageName.isEmpty()) this else "$packageName.$this"