Fix portability issues and move JVM-only test

lynglib/src/commonMain/kotlin/net/sergeych/lyng/Compiler.kt

@@ -1192,7 +1192,9 @@ class Compiler(
             val found = LinkedHashMap<String, Pair<ModuleScope, ObjRecord>>()
             collectModuleRecordMatches(module.scope, name, mutableSetOf(), found)
             for ((pkg, pair) in found) {
-                moduleMatches.putIfAbsent(pkg, ImportedModule(pair.first, module.pos) to pair.second)
+                if (!moduleMatches.containsKey(pkg)) {
+                    moduleMatches[pkg] = ImportedModule(pair.first, module.pos) to pair.second
+                }
             }
         }
         if (seedRecord != null) {
@@ -1241,7 +1243,9 @@ class Compiler(
         if (!visited.add(scope.packageName)) return
         val record = scope.objects[name]
         if (record != null && record.visibility.isPublic) {
-            out.putIfAbsent(scope.packageName, scope to record)
+            if (!out.containsKey(scope.packageName)) {
+                out[scope.packageName] = scope to record
+            }
         }
         for (child in scope.importedModules) {
             collectModuleRecordMatches(child, name, visited, out)

lynglib/src/commonMain/kotlin/net/sergeych/lyng/Scope.kt

@@ -80,23 +80,17 @@ open class Scope(
             extras.isEmpty() -> emptyList()
             else -> {
                 try {
-                    if (extras is MutableList<*>) {
-                        synchronized(extras) { extras.toList() }
-                    } else {
-                        extras.toList()
-                    }
+                    extras.toList()
                 } catch (_: Exception) {
                     emptyList()
                 }
             }
         }
-        synchronized(thisVariants) {
-            thisVariants.clear()
-            thisVariants.add(primary)
-            for (obj in extrasSnapshot) {
-                if (obj !== primary && !thisVariants.contains(obj)) {
-                    thisVariants.add(obj)
-                }
+        thisVariants.clear()
+        thisVariants.add(primary)
+        for (obj in extrasSnapshot) {
+            if (obj !== primary && !thisVariants.contains(obj)) {
+                thisVariants.add(obj)
             }
         }
     }