[FIR] Lookup in local sources in default imports based on the flag

Reuse ALLOW_KOTLIN_PACKAGE for that

compiler/testData/codegen/bytecodeText/constants/inlineUnsignedIntConstant.kt

@@ -1,4 +1,5 @@
 // !LANGUAGE: +InlineClasses
+// ALLOW_KOTLIN_PACKAGE
 
 // FILE: uint.kt
 
@@ -8,9 +9,6 @@ inline class UInt(val value: Int)
 
 // FILE: test.kt
 
-//this import in required in FIR because default imports don't search in local sources atm
-import kotlin.UInt
-
 const val u = UInt(14)
 
 fun foo() {