Add kotlinp, a tool to print Kotlin metadata in class/module files

At the moment, it's not published anywhere, but that may change soon

 #KT-23198

libraries/tools/kotlinp/testData/SimpleClass.kt

@@ -0,0 +1,13 @@
+class SimpleClass<in A>(val p: Int = 42) {
+    constructor(s: Array<String?>?) : this(s?.size ?: 0)
+
+    var x: Long = p.toLong()
+        external get
+        @JvmName("SET_X") set
+
+    internal fun <U : A, V, A> A.f(vararg z: Map<V, U?>): Set<*> where V : A {
+        error("")
+    }
+
+    protected suspend inline fun <reified T> g(crossinline a: () -> A, noinline b: suspend () -> T) {}
+}