Remove default import "kotlin.reflect"

Basic reflection is usable without any imports (with :: literals)

This reverts commit 9503056dd5.

compiler/testData/diagnostics/testsWithStdLib/callableReference/function/longQualifiedName.kt

@@ -8,6 +8,8 @@ class D {
 
 // FILE: b.kt
 
+import kotlin.reflect.KMemberFunction0
+
 fun main() {
     val x = a.b.c.D::foo