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.

compiler/tests-common-jvm6/build.gradle.kts

@@ -5,7 +5,7 @@ jvmTarget = "1.6"
 
 dependencies {
     compile(project(":kotlin-stdlib"))
-    compile(project(":kotlin-test:kotlin-test-jvm"))
+    testCompile(project(":kotlin-test:kotlin-test-jvm"))
 }
 
 sourceSets {