Support KClass.functions and declaredFunctions

compiler/testData/codegen/boxWithStdlib/reflection/parameters/functionParameterNameAndIndex.kt

@@ -5,6 +5,8 @@ fun foo(bar: String): Int = bar.length()
 
 class A(val c: String) {
     fun foz(baz: Int) {}
+
+    fun Double.mext(mez: Long) {}
 }
 
 fun Int.qux(zux: String) {}
@@ -21,6 +23,8 @@ fun box(): String {
     checkParameters(A::foz, listOf(null, "baz"))
     checkParameters(Int::qux, listOf(null, "zux"))
 
+    checkParameters(A::class.functions.single { it.name == "mext" }, listOf(null, null, "mez"))
+
     checkParameters(::A, listOf("c"))
 
     return "OK"