Add Flag.IS_VALUE for value classes to kotlinx-metadata-jvm

#KT-44783 Fixed

libraries/tools/kotlinp/testData/ValueClass.kt

@@ -0,0 +1,2 @@
+@JvmInline
+value class Z(val s: String)

libraries/tools/kotlinp/testData/ValueClass.txt

@@ -0,0 +1,29 @@
+// Z.class
+// ------------------------------------------
+// requires language version 1.3.0 (level=ERROR)
+public final value class Z : kotlin/Any {
+
+  // requires language version 1.3.0 (level=ERROR)
+  // signature: constructor-impl(Ljava/lang/String;)Ljava/lang/String;
+  public constructor(s: kotlin/String)
+
+  // signature: equals-impl(Ljava/lang/String;Ljava/lang/Object;)Z
+  public open /* synthesized */ operator fun equals(other: kotlin/Any?): kotlin/Boolean
+
+  // signature: hashCode-impl(Ljava/lang/String;)I
+  public open /* synthesized */ fun hashCode(): kotlin/Int
+
+  // signature: toString-impl(Ljava/lang/String;)Ljava/lang/String;
+  public open /* synthesized */ fun toString(): kotlin/String
+
+  // field: s:Ljava/lang/String;
+  // getter: getS()Ljava/lang/String;
+  public final val s: kotlin/String
+    public final get
+
+  // module name: test-module
+}
+// META-INF/test-module.kotlin_module
+// ------------------------------------------
+module {
+}