[Swift Export] KT-65008: support simple top-level properties

Merge-request: KT-MR-14131
Merged-by: Gleb Lukianets <Gleb.Lukianets@jetbrains.com>

native/swift/sir-compiler-bridge/testData/property_accessors/expected.kt

@@ -0,0 +1,13 @@
+import kotlin.native.internal.ExportedBridge
+
+@ExportedBridge("getter_bridge")
+public fun getter_bridge(): Boolean {
+    val result = variable()
+    return result
+}
+
+@ExportedBridge("setter_bridge")
+public fun setter_bridge(newValue: Boolean): Unit {
+    val result = variable(newValue)
+    return result
+}