Minor, return a set in JavaModuleGraph.getAllDependencies

To prevent duplicate roots to be added

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/ClasspathRootsResolver.kt

@@ -191,8 +191,7 @@ internal class ClasspathRootsResolver(
             else -> computeDefaultRootModules() + additionalModules
         }
 
-        val allDependencies = javaModuleGraph.getAllDependencies(rootModules).toMutableList()
-
+        val allDependencies = javaModuleGraph.getAllDependencies(rootModules)
         if (allDependencies.any { moduleName -> javaModuleFinder.findModule(moduleName) is JavaModule.Automatic }) {
             // According to java.lang.module javadoc, if at least one automatic module is added to the module graph,
             // all observable automatic modules should be added.

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/modules/JavaModuleGraph.kt

@@ -22,8 +22,8 @@ class JavaModuleGraph(finder: JavaModuleFinder) {
     private val module: (String) -> JavaModule? =
             LockBasedStorageManager.NO_LOCKS.createMemoizedFunctionWithNullableValues(finder::findModule)
 
-    fun getAllDependencies(moduleNames: List<String>): List<String> {
-        val visited = moduleNames.toMutableSet()
+    fun getAllDependencies(moduleNames: List<String>): LinkedHashSet<String> {
+        val visited = LinkedHashSet(moduleNames)
 
         // Every module implicitly depends on java.base
         visited += "java.base"
@@ -55,7 +55,7 @@ class JavaModuleGraph(finder: JavaModuleFinder) {
             }
         }
 
-        return visited.toList()
+        return visited
     }
 
     fun reads(moduleName: String, dependencyName: String): Boolean {