Parcelize: Enable ParcelableDeclarationChecker with the parcelize plugin

Previously, the ParcelableDeclarationChecker was only enabled as part of
the view extensions. In particular, the checker was not enabled for the
parcelize test suite.

plugins/android-extensions/android-extensions-compiler/testData/parcel/box/customSerializerBoxing.kt

@@ -31,7 +31,7 @@ data class Test(
         @TypeParceler<Long, Parceler2> val c: Long,
         @TypeParceler<Int, Parceler1> val d: List<Int>,
         @TypeParceler<Long, Parceler2> val e: LongArray
-)
+) : Parcelable
 
 fun box() = parcelTest { parcel ->
     val test = Test(5, 5, 50L, listOf(1, 2, 3), longArrayOf(3, 2, 1))

plugins/android-extensions/android-extensions-compiler/testData/parcel/box/customSerializerSimple.kt

@@ -32,7 +32,7 @@ data class Test(
         @TypeParceler<String, Parceler1> val b: String,
         @TypeParceler<String, Parceler3> val c: CharSequence,
         val d: @WriteWith<Parceler3> String
-)
+) : Parcelable
 
 fun box() = parcelTest { parcel ->
     val test = Test("Abc", "Abc", "Abc", "Abc")

plugins/android-extensions/android-extensions-compiler/testData/parcel/box/customSerializerWriteWith.kt

@@ -33,7 +33,7 @@ data class Test(
         val c: List<@WriteWith<Parceler1> String>,
         val d: @WriteWith<Parceler2> List<String>,
         val e: @WriteWith<Parceler2> List<@WriteWith<Parceler1> String>
-)
+) : Parcelable
 
 fun box() = parcelTest { parcel ->
     val test = Test("Abc", "Abc", listOf("A", "bc"), listOf("A", "bc"), listOf("A", "bc"))