[Test] Disable gradle test parallelization if JUnit 5 is enabled

buildSrc/src/main/kotlin/tasks.kt

@@ -70,6 +70,10 @@ fun Task.dependsOnKotlinGradlePluginPublish() {
     }
 }
 
+/**
+ * @param parallel is redundant if @param jUnit5Enabled is true, because
+ *   JUnit5 supports parallel test execution by itself, without gradle help
+ */
 fun Project.projectTest(
     taskName: String = "test",
     parallel: Boolean = false,
@@ -193,7 +197,7 @@ fun Project.projectTest(
         }
     }
 
-    if (parallel) {
+    if (parallel && !jUnit5Enabled) {
         maxParallelForks =
             project.findProperty("kotlin.test.maxParallelForks")?.toString()?.toInt()
                 ?: (Runtime.getRuntime().availableProcessors() / if (kotlinBuildProperties.isTeamcityBuild) 2 else 4).coerceAtLeast(1)

compiler/fir/analysis-tests/build.gradle.kts

@@ -78,7 +78,7 @@ if (kotlinBuildProperties.isInJpsBuildIdeaSync) {
     }
 }
 
-projectTest(parallel = true, jUnit5Enabled = true) {
+projectTest(jUnit5Enabled = true) {
     dependsOn(":dist")
     workingDir = rootDir
     jvmArgs!!.removeIf { it.contains("-Xmx") }

compiler/fir/fir2ir/build.gradle.kts

@@ -58,7 +58,7 @@ if (kotlinBuildProperties.isInJpsBuildIdeaSync) {
     }
 }
 
-projectTest(parallel = true, jUnit5Enabled = true) {
+projectTest(jUnit5Enabled = true) {
     workingDir = rootDir
     useJUnitPlatform()
 }

compiler/tests-common-new/build.gradle.kts

@@ -69,7 +69,7 @@ if (kotlinBuildProperties.isInJpsBuildIdeaSync) {
     }
 }
 
-projectTest(parallel = true, jUnit5Enabled = true) {
+projectTest(jUnit5Enabled = true) {
     dependsOn(":dist")
     workingDir = rootDir
     jvmArgs!!.removeIf { it.contains("-Xmx") }