[FIR] Extract SyntheticFunctionsCache from builtins provider into separate one

This is needed because now set of available synthetic functional interfaces
  depends on session, because each module can contain different plugins,
  which provide different kinds of functional types

compiler/fir/cones/src/org/jetbrains/kotlin/fir/types/ConeFunctionalTypeKind.kt

@@ -130,3 +130,12 @@ abstract class ConeFunctionalTypeKind internal constructor(
         override fun nonReflectKind(): ConeFunctionalTypeKind = SuspendFunction
     }
 }
+
+val ConeFunctionalTypeKind.isBuiltin: Boolean
+    get() = when (this) {
+        ConeFunctionalTypeKind.Function,
+        ConeFunctionalTypeKind.KFunction,
+        ConeFunctionalTypeKind.SuspendFunction,
+        ConeFunctionalTypeKind.KSuspendFunction -> true
+        else -> false
+    }