remove support for 'trait' keyword

js/js.translator/testData/trait/cases/checkImplementationCharacteristics.kt

@@ -1,10 +1,10 @@
 package foo
 
-public trait A {
+public interface A {
     fun foo() {
     }
 }
-public trait B : A {
+public interface B : A {
     fun boo() {
     }
 }

js/js.translator/testData/trait/cases/classDerivesFromClassAndTrait.kt

@@ -5,7 +5,7 @@ open class A() {
     val value = "BAR"
 }
 
-trait Test {
+interface Test {
     fun addFoo(s: String): String {
         return s + "FOO"
     }

js/js.translator/testData/trait/cases/classDerivesFromTraitAndClass.kt

@@ -5,7 +5,7 @@ open class A() {
     val value = "BAR"
 }
 
-trait Test {
+interface Test {
     fun addFoo(s: String): String {
         return s + "FOO"
     }

js/js.translator/testData/trait/cases/definitionOrder.kt

@@ -32,16 +32,16 @@ open class A() : F {
     }
 }
 
-trait F : G {
+interface F : G {
     fun bar() = "F"
 }
 
 // KT-3437
-trait G : H
-trait K : H
-trait L
-trait H : L
-trait Dummy
+interface G : H
+interface K : H
+interface L
+interface H : L
+interface Dummy
 
 fun box(): Boolean {
     return (C().order == "ABC") && (D().order == "ABD") && (E().order == "AE") && (C().bar() == "F") && (A().bar() == "F")

js/js.translator/testData/trait/cases/example.kt

@@ -1,6 +1,6 @@
 package foo
 
-trait AL {
+interface AL {
     fun get(index: Int): Any? = null
 }
 

js/js.translator/testData/trait/cases/funDelegation.kt

@@ -4,7 +4,7 @@ open class Base() {
     fun n(n: Int): Int = n + 1
 }
 
-trait Abstract {
+interface Abstract {
 }
 
 class Derived1() : Base(), Abstract {

js/js.translator/testData/trait/cases/traitAddsFunctionsToClass.kt

@@ -1,6 +1,6 @@
 package foo
 
-trait Test {
+interface Test {
     fun addFoo(s: String): String {
         return s + "FOO"
     }

js/js.translator/testData/trait/cases/traitExtendsTrait.kt

@@ -1,12 +1,12 @@
 package foo
 
-trait Test {
+interface Test {
     fun addFoo(s: String): String {
         return s + "FOO"
     }
 }
 
-trait ExtendedTest : Test {
+interface ExtendedTest : Test {
     fun hooray(): String {
         return "hooray"
     }

js/js.translator/testData/trait/cases/traitExtendsTwoTraits.kt

@@ -1,18 +1,18 @@
 package foo
 
-trait A {
+interface A {
     fun addFoo(s: String): String {
         return s + "FOO"
     }
 }
 
-trait B {
+interface B {
     fun hooray(): String {
         return "hooray"
     }
 }
 
-trait AD : A, B {
+interface AD : A, B {
 
 }