Introduce binary representation for annotations

Will be used where annotations can't be stored elsewhere: for example,
built-ins, JS, type annotations on JDK<8

compiler/testData/serialization/annotationArguments/enum.kt

@@ -0,0 +1,18 @@
+package test
+
+enum class Weapon {
+    ROCK
+    PAPER
+    SCISSORS
+}
+
+annotation class JustEnum(val weapon: Weapon)
+
+annotation class EnumArray(val enumArray: Array<Weapon>)
+
+JustEnum(Weapon.SCISSORS)
+EnumArray(array())
+class C1
+
+EnumArray(array(Weapon.PAPER, Weapon.ROCK))
+class C2