Replace IoPackage legacy facade with corresponding package parts.

Original commit: fa491c8f1f

jps/jps-plugin/src/org/jetbrains/kotlin/jps/build/KotlinBuilderModuleScriptGenerator.java

@@ -22,7 +22,7 @@ import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.util.containers.ContainerUtil;
 import com.intellij.util.containers.MultiMap;
 import kotlin.CollectionsKt;
-import kotlin.io.IoPackage;
+import kotlin.io.FilesKt;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jps.ModuleChunk;
@@ -123,7 +123,7 @@ public class KotlinBuilderModuleScriptGenerator {
             @Override
             public boolean value(File file) {
                 if (!file.exists()) {
-                    String extension = IoPackage.getExtension(file);
+                    String extension = FilesKt.getExtension(file);
 
                     // Don't filter out files, we want to report warnings about absence through the common place
                     if (!(extension.equals("class") || extension.equals("jar"))) {