Minor, simplify JS-related build files a bit

* remove test roots in modules which have no tests
* 1.8 is already the default JVM target in the project
* replace compilation dependency on kotlin-reflect with runtime

compiler/cli/cli-js-klib/build.gradle.kts

@@ -3,12 +3,10 @@ plugins {
     id("jps-compatible")
 }
 
-jvmTarget = "1.8"
-
 dependencies {
     compile(project(":compiler:cli"))
     compile(project(":compiler:ir.serialization.js"))
-    compile(project(":kotlin-reflect"))
+    runtime(project(":kotlin-reflect"))
     compile(intellijDep()) { includeJars("picocontainer", "trove4j", "guava", "jdom", rootProject = rootProject) }
     compile(intellijCoreDep()) { includeJars("intellij-core") }
 }