Light classes: generate ACC_STATIC for DefaultImpls classes

To provide consistency between light classes and their delegates

IdeLightClass#testExtendingInterfaceWithDefaultImpls still failing since
    we do not generate implementations delegating to DefaultImpls of superinterfaces

compiler/backend/src/org/jetbrains/kotlin/codegen/InterfaceImplBodyCodegen.kt

@@ -48,8 +48,10 @@ class InterfaceImplBodyCodegen(
         get() = (v as InterfaceImplClassBuilder).isAnythingGenerated
 
     override fun generateDeclaration() {
+        val codegenFlags = ACC_PUBLIC or ACC_FINAL or ACC_SUPER
+        val flags = if (state.classBuilderMode == ClassBuilderMode.LIGHT_CLASSES) codegenFlags or ACC_STATIC else codegenFlags
         v.defineClass(
-                myClass.psiOrParent, state.classFileVersion, ACC_PUBLIC or ACC_FINAL or ACC_SUPER,
+                myClass.psiOrParent, state.classFileVersion, flags,
                 typeMapper.mapDefaultImpls(descriptor).internalName,
                 null, "java/lang/Object", ArrayUtil.EMPTY_STRING_ARRAY
         )

compiler/testData/asJava/lightClasses/ExtendingInterfaceWithDefaultImpls.java

@@ -2,11 +2,11 @@ public interface B extends p.A {
     @org.jetbrains.annotations.NotNull
     java.lang.String b();
 
-    final class DefaultImpls {
+    static final class DefaultImpls {
         @org.jetbrains.annotations.NotNull
         public static java.lang.String b(p.B $this) { /* compiled code */ }
 
         @org.jetbrains.annotations.NotNull
         public static java.lang.String a(p.B $this) { /* compiled code */ }
     }
-}
+}

compiler/testData/asJava/lightClasses/compilationErrors/PrivateInTrait.java

@@ -1,5 +1,5 @@
 public interface PrivateInTrait {
-    final class DefaultImpls {
+    static final class DefaultImpls {
         private static java.lang.String getNn(PrivateInTrait $this) { /* compiled code */ }
 
         private static void setNn(PrivateInTrait $this, java.lang.String value) { /* compiled code */ }

compiler/tests-common/org/jetbrains/kotlin/asJava/LightClassTestCommon.kt

@@ -64,5 +64,5 @@ object LightClassTestCommon {
     // Actual text for light class is generated with ClsElementImpl.appendMirrorText() that can find empty DefaultImpl inner class in stubs
     // for all interfaces. This inner class can't be used in Java as it generally is not seen from light classes built from Kotlin sources.
     // It is also omitted during classes generation in backend so it also absent in light classes built from compiled code.
-    fun removeEmptyDefaultImpls(text: String) : String = text.replace("\n    final class DefaultImpls {\n    }\n", "")
+    fun removeEmptyDefaultImpls(text: String) : String = text.replace("\n    static final class DefaultImpls {\n    }\n", "")
 }