Add Kotlin package FQ name to kotlin.Metadata

It might differ from the JVM package FQ name if the JvmPackageName
annotation is used. This will be useful for faster indexing in the IDE
and for reflection

compiler/testData/codegen/box/jvmPackageName/metadataField.kt

@@ -0,0 +1,28 @@
+// TARGET_BACKEND: JVM
+// WITH_RUNTIME
+// LANGUAGE_VERSION: 1.2
+
+// FILE: foo.kt
+
+@file:Suppress("INVISIBLE_REFERENCE", "INVISIBLE_MEMBER")
+@file:JvmPackageName("baz.foo.quux.bar")
+package foo.bar
+
+fun f() {}
+
+// FILE: bar.kt
+
+@file:Suppress("INVISIBLE_REFERENCE", "INVISIBLE_MEMBER")
+
+fun getPackageName(classFqName: String): String =
+        Class.forName(classFqName).getAnnotation(Metadata::class.java).pn
+
+fun box(): String {
+    val bar = getPackageName("BarKt")
+    if (bar != "") return "Fail 1: $bar"
+
+    val foo = getPackageName("baz.foo.quux.bar.FooKt")
+    if (foo != "foo.bar") return "Fail 2: $foo"
+
+    return "OK"
+}