Reflection: add API for declaration modifiers

#KT-10447 Fixed

compiler/testData/codegen/box/reflection/modifiers/classes.kt

@@ -0,0 +1,43 @@
+// WITH_REFLECT
+
+import kotlin.test.assertTrue
+import kotlin.test.assertFalse
+
+sealed class S {
+    data class DataClass(val x: Int) : S()
+    inner class InnerClass
+    companion object
+    object NonCompanionObject
+}
+
+fun box(): String {
+    assertTrue(S::class.isSealed)
+    assertFalse(S::class.isFinal)
+    assertFalse(S::class.isOpen)
+    assertFalse(S::class.isAbstract)
+    assertFalse(S::class.isData)
+    assertFalse(S::class.isInner)
+    assertFalse(S::class.isCompanion)
+
+    assertFalse(S.DataClass::class.isSealed)
+    assertTrue(S.DataClass::class.isData)
+    assertFalse(S.DataClass::class.isInner)
+    assertFalse(S.DataClass::class.isCompanion)
+
+    assertFalse(S.InnerClass::class.isSealed)
+    assertFalse(S.InnerClass::class.isData)
+    assertTrue(S.InnerClass::class.isInner)
+    assertFalse(S.InnerClass::class.isCompanion)
+
+    assertFalse(S.Companion::class.isSealed)
+    assertFalse(S.Companion::class.isData)
+    assertFalse(S.Companion::class.isInner)
+    assertTrue(S.Companion::class.isCompanion)
+
+    assertFalse(S.NonCompanionObject::class.isSealed)
+    assertFalse(S.NonCompanionObject::class.isData)
+    assertFalse(S.NonCompanionObject::class.isInner)
+    assertFalse(S.NonCompanionObject::class.isCompanion)
+
+    return "OK"
+}