Make projectTests type of dependency transitive on testRuntime dependencies

`tests-jar` configuration now extends testRuntime instead of testCompile
(note that testRuntime extends testCompile),
and projectTests() dependency shortcut makes it transitive.

This is required to depend on test utility modules producing `-tests` jar instead of default one
without listing all their transitive dependencies.

buildSrc/src/main/kotlin/artifacts.kt

@@ -37,7 +37,7 @@ fun Project.classesDirsArtifact(): FileCollection {
 }
 
 fun Project.testsJar(body: Jar.() -> Unit = {}): Jar {
-    val testsJarCfg = configurations.getOrCreate("tests-jar").extendsFrom(configurations["testCompile"])
+    val testsJarCfg = configurations.getOrCreate("tests-jar").extendsFrom(configurations["testRuntime"])
 
     return task<Jar>("testsJar") {
         dependsOn("testClasses")

buildSrc/src/main/kotlin/dependencies.kt

@@ -66,7 +66,7 @@ fun Project.ideaUltimatePluginDeps(vararg artifactBaseNames: String, plugin: Str
 fun Project.kotlinDep(artifactBaseName: String, version: String): String = "org.jetbrains.kotlin:kotlin-$artifactBaseName:$version"
 
 fun DependencyHandler.projectDist(name: String): Dependency = project(name, configuration = "distJar").apply { isTransitive = false }
-fun DependencyHandler.projectTests(name: String): Dependency = project(name, configuration = "tests-jar").apply { isTransitive = false }
+fun DependencyHandler.projectTests(name: String): Dependency = project(name, configuration = "tests-jar")
 fun DependencyHandler.projectRuntimeJar(name: String): Dependency = project(name, configuration = "runtimeJar")
 fun DependencyHandler.projectArchives(name: String): Dependency = project(name, configuration = "archives")
 fun DependencyHandler.projectClasses(name: String): Dependency = project(name, configuration = "classes-dirs")