Configuration: Don't create kotlinc.xml if the settings don't differ from the defaults

#KT-16647 Fixed

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/CommonCompilerArguments.java

@@ -99,6 +99,15 @@ public abstract class CommonCompilerArguments implements Serializable {
 
     public List<String> unknownExtraFlags = new SmartList<String>();
 
+    @NotNull
+    public static CommonCompilerArguments createDefaultInstance() {
+        DummyImpl arguments = new DummyImpl();
+        arguments.coroutinesEnable = false;
+        arguments.coroutinesWarn = true;
+        arguments.coroutinesError = false;
+        return arguments;
+    }
+
     @NotNull
     public String executableScriptFileName() {
         return "kotlinc";

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/K2JSCompilerArguments.java

@@ -71,6 +71,13 @@ public class K2JSCompilerArguments extends CommonCompilerArguments {
     @ValueDescription("<path>")
     public String outputPostfix;
 
+    @NotNull
+    public static K2JSCompilerArguments createDefaultInstance() {
+        K2JSCompilerArguments arguments = new K2JSCompilerArguments();
+        arguments.moduleKind = K2JsArgumentConstants.MODULE_PLAIN;
+        return arguments;
+    }
+
     @Override
     @NotNull
     public String executableScriptFileName() {

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/K2JVMCompilerArguments.java

@@ -18,6 +18,7 @@ package org.jetbrains.kotlin.cli.common.arguments;
 
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.kotlin.cli.common.parser.com.sampullara.cli.Argument;
+import org.jetbrains.kotlin.config.JvmTarget;
 
 public class K2JVMCompilerArguments extends CommonCompilerArguments {
     public static final long serialVersionUID = 0L;
@@ -113,10 +114,16 @@ public class K2JVMCompilerArguments extends CommonCompilerArguments {
     // Paths to output directories for friend modules.
     public String[] friendPaths;
 
+    @NotNull
+    public static K2JVMCompilerArguments createDefaultInstance() {
+        K2JVMCompilerArguments arguments = new K2JVMCompilerArguments();
+        arguments.jvmTarget = JvmTarget.DEFAULT.getDescription();
+        return arguments;
+    }
+
     @Override
     @NotNull
     public String executableScriptFileName() {
         return "kotlinc-jvm";
     }
-
 }