reflect: add reflect.TypeOf

This is the beginning of true reflection support in TinyGo.

testdata/reflect.go

@@ -0,0 +1,12 @@
+package main
+
+import "reflect"
+
+type myint int
+
+func main() {
+	println("matching types")
+	println(reflect.TypeOf(int(3)) == reflect.TypeOf(int(5)))
+	println(reflect.TypeOf(int(3)) == reflect.TypeOf(uint(5)))
+	println(reflect.TypeOf(myint(3)) == reflect.TypeOf(int(5)))
+}

testdata/reflect.txt

@@ -0,0 +1,4 @@
+matching types
+true
+false
+false