Add KFunction.name, support reflection for function references

#KT-7694 Fixed

compiler/testData/codegen/boxWithStdlib/reflection/functions/localFunctionName.kt

@@ -0,0 +1,5 @@
+fun box(): String {
+    fun OK() {}
+
+    return ::OK.name
+}

compiler/testData/codegen/boxWithStdlib/reflection/functions/platformName.kt

@@ -0,0 +1,6 @@
+import kotlin.platform.platformName
+
+@platformName("Fail")
+fun OK() {}
+
+fun box() = ::OK.name

compiler/testData/codegen/boxWithStdlib/reflection/functions/simpleNames.kt

@@ -0,0 +1,16 @@
+import kotlin.test.assertEquals
+
+fun foo() {}
+
+class A {
+    fun bar() = ""
+}
+
+fun Int.baz() = this
+
+fun box(): String {
+    assertEquals("foo", ::foo.name)
+    assertEquals("bar", A::bar.name)
+    assertEquals("baz", Int::baz.name)
+    return "OK"
+}