Make kotlin.Metadata public

Prohibit explicit usage of `@Metadata` to prevent possible
AnnotationFormatError at runtime

 #KT-23602 Fixed

compiler/testData/diagnostics/testsWithStdLib/annotations/explicitMetadata.kt

@@ -1,5 +1,3 @@
-// !DIAGNOSTICS: -INVISIBLE_MEMBER -INVISIBLE_REFERENCE -EXPOSED_PARAMETER_TYPE
-
 <!EXPLICIT_METADATA_IS_DISALLOWED!>@Metadata<!>
 class A
 

libraries/stdlib/jvm/runtime/kotlin/Metadata.kt

@@ -11,7 +11,8 @@ package kotlin
  */
 @Retention(AnnotationRetention.RUNTIME)
 @Target(AnnotationTarget.CLASS)
-internal annotation class Metadata(
+@SinceKotlin("1.3")
+public annotation class Metadata(
     /**
      * A kind of the metadata this annotation encodes. Kotlin compiler recognizes the following kinds (see KotlinClassHeader.Kind):
      *

libraries/tools/binary-compatibility-validator/reference-public-api/kotlin-runtime.txt

@@ -26,6 +26,17 @@ public class kotlin/KotlinNullPointerException : java/lang/NullPointerException
 	public fun <init> (Ljava/lang/String;)V
 }
 
+public abstract interface annotation class kotlin/Metadata : java/lang/annotation/Annotation {
+	public abstract fun bv ()[I
+	public abstract fun d1 ()[Ljava/lang/String;
+	public abstract fun d2 ()[Ljava/lang/String;
+	public abstract fun k ()I
+	public abstract fun mv ()[I
+	public abstract fun pn ()Ljava/lang/String;
+	public abstract fun xi ()I
+	public abstract fun xs ()Ljava/lang/String;
+}
+
 public class kotlin/NoWhenBranchMatchedException : java/lang/RuntimeException {
 	public fun <init> ()V
 	public fun <init> (Ljava/lang/String;)V

libraries/tools/binary-compatibility-validator/reference-public-api/kotlin-stdlib-runtime-merged.txt

@@ -89,6 +89,17 @@ public final class kotlin/LazyThreadSafetyMode : java/lang/Enum {
 	public static fun values ()[Lkotlin/LazyThreadSafetyMode;
 }
 
+public abstract interface annotation class kotlin/Metadata : java/lang/annotation/Annotation {
+	public abstract fun bv ()[I
+	public abstract fun d1 ()[Ljava/lang/String;
+	public abstract fun d2 ()[Ljava/lang/String;
+	public abstract fun k ()I
+	public abstract fun mv ()[I
+	public abstract fun pn ()Ljava/lang/String;
+	public abstract fun xi ()I
+	public abstract fun xs ()Ljava/lang/String;
+}
+
 public class kotlin/NoWhenBranchMatchedException : java/lang/RuntimeException {
 	public fun <init> ()V
 	public fun <init> (Ljava/lang/String;)V