Fixup for 9b861739 (the fix for KT-35942)

* Don't include the JS friend paths into the classpath
* Fix binary compatibility with Gradle < 5.1

Issue #KT-35942

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/kotlinCompilations.kt

@@ -26,6 +26,7 @@ import org.jetbrains.kotlin.gradle.plugin.sources.getSourceSetHierarchy
 import org.jetbrains.kotlin.gradle.tasks.AbstractKotlinCompile
 import org.jetbrains.kotlin.gradle.tasks.locateTask
 import org.jetbrains.kotlin.gradle.utils.addExtendsFromRelation
+import org.jetbrains.kotlin.gradle.utils.archivePathCompatible
 import org.jetbrains.kotlin.gradle.utils.lowerCamelCaseName
 import java.io.File
 import java.util.*
@@ -211,7 +212,7 @@ abstract class AbstractKotlinCompilation<T : KotlinCommonOptions>(
                 // that depends on this module's production part, include the main artifact in the friend artifacts, lazily:
                 files(
                     provider {
-                        listOfNotNull(tasks.withType(AbstractArchiveTask::class.java).findByName(target.artifactsTaskName)?.archiveFile)
+                        listOfNotNull(tasks.withType(AbstractArchiveTask::class.java).findByName(target.artifactsTaskName)?.archivePathCompatible)
                     }
                 )
             } else files()

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/Tasks.kt

@@ -548,7 +548,10 @@ open class Kotlin2JsCompile : AbstractKotlinCompile<K2JSCompilerArguments>(), Ko
     internal val friendDependencies: List<String>
         get() {
             val filter = libraryFilter
-            return friendPaths.filter { filter(File(it)) }
+            return friendPaths.filter {
+                val file = File(it)
+                file.exists() && filter(file)
+            }
         }
 
     @Suppress("unused")
@@ -605,7 +608,7 @@ open class Kotlin2JsCompile : AbstractKotlinCompile<K2JSCompilerArguments>(), Ko
             .filter { it.exists() && libraryFilter(it) }
             .map { it.canonicalPath }
 
-        args.libraries = (dependencies + friendDependencies).distinct().let {
+        args.libraries = dependencies.distinct().let {
             if (it.isNotEmpty())
                 it.joinToString(File.pathSeparator) else
                 null