add test for "external" macro methods (see #7453)

tests/misc/projects/Issue7453/Main.hx

@@ -0,0 +1,7 @@
+class Main {
+	static function main() {
+		js.Browser.console.log("Version " + getVersion());
+	}
+
+	static macro function getVersion();
+}

tests/misc/projects/Issue7453/Main.macro.hx

@@ -0,0 +1,3 @@
+class Main {
+	static function getVersion() return macro 1;
+}

tests/misc/projects/Issue7453/compile.hxml

@@ -0,0 +1,4 @@
+-main Main
+-js main.js
+--no-output
+# should just compile