[FIR] Introduce the PluginGenerated source kind

Make parcelize work consistently with
`FirOverrideChecker`.

Actually, there is a philosophical question about
what to do when a plugin generates a class
in a new package, and this class is red code
(for instance, doesn't implement an abstract
member from a supertype). There's no source
to report such an error, but we probably do
want to run checkers to avoid trying to
compile red code to binaries (because it may
crash in backend, or it may silently work).

plugins/parcelize/parcelize-compiler/testData/diagnostics/withoutParcelableSupertype.fir.kt

@@ -0,0 +1,20 @@
+package test
+
+import kotlinx.parcelize.Parcelize
+import android.os.Parcelable
+
+@Parcelize
+class <!NOTHING_TO_OVERRIDE, NOTHING_TO_OVERRIDE, NO_PARCELABLE_SUPERTYPE!>Without<!>(val firstName: String, val secondName: String, val age: Int)
+
+@Parcelize
+class With(val firstName: String, val secondName: String, val age: Int) : Parcelable
+
+interface MyParcelableIntf : Parcelable
+
+abstract class MyParcelableCl : Parcelable
+
+@Parcelize
+class WithIntfSubtype(val firstName: String, val secondName: String, val age: Int) : MyParcelableIntf
+
+@Parcelize
+class WithClSubtype(val firstName: String, val secondName: String, val age: Int) : MyParcelableCl()

plugins/parcelize/parcelize-compiler/testData/diagnostics/withoutParcelableSupertype.kt

@@ -1,4 +1,3 @@
-// FIR_IDENTICAL
 package test
 
 import kotlinx.parcelize.Parcelize

plugins/parcelize/parcelize-compiler/testData/diagnostics/wrongAnnotationTarget.fir.kt

@@ -0,0 +1,25 @@
+package test
+
+import kotlinx.parcelize.Parcelize
+import android.os.Parcelable
+
+@Parcelize
+interface <!PARCELABLE_SHOULD_BE_CLASS!>Intf<!> : Parcelable
+
+@Parcelize
+object <!NOTHING_TO_OVERRIDE, NOTHING_TO_OVERRIDE, NO_PARCELABLE_SUPERTYPE!>Obj<!>
+
+class A {
+    @Parcelize
+    companion <!NOTHING_TO_OVERRIDE, NOTHING_TO_OVERRIDE, NO_PARCELABLE_SUPERTYPE!>object<!> {
+        fun foo() {}
+    }
+}
+
+@Parcelize
+enum class <!NOTHING_TO_OVERRIDE, NOTHING_TO_OVERRIDE, NO_PARCELABLE_SUPERTYPE!>Enum<!> {
+    WHITE, BLACK
+}
+
+@Parcelize
+annotation class <!NOTHING_TO_OVERRIDE, NOTHING_TO_OVERRIDE, PARCELABLE_SHOULD_BE_CLASS!>Anno<!>

plugins/parcelize/parcelize-compiler/testData/diagnostics/wrongAnnotationTarget.kt

@@ -1,4 +1,3 @@
-// FIR_IDENTICAL
 package test
 
 import kotlinx.parcelize.Parcelize