reenable utf8 tests (restricted to BMP chars)

tests/unit/unitstd/haxe/Utf8.unit.hx

@@ -1,4 +1,5 @@
 #if false
+// disabled tests with outside BMP chars (will be reenabled when we support them)
 var str = "あ𠀀い";
 haxe.Utf8.length(str) == 3;
 haxe.Utf8.charCodeAt(str, 0) == 0x3042;
@@ -15,4 +16,23 @@ haxe.Utf8.compare(haxe.Utf8.sub(str, 1, 2), "𠀀い") == 0;
 haxe.Utf8.compare(haxe.Utf8.sub(str, 0, 0), "") == 0;
 haxe.Utf8.compare(haxe.Utf8.sub(str, 1, 0), "") == 0;
 haxe.Utf8.compare(haxe.Utf8.sub(str, 9, 0), "") == 0;
-#end
+#end
+
+
+// same tests with BMP chars (actually UCS2 compliance only)
+var str = "あéい";
+haxe.Utf8.length(str) == 3;
+haxe.Utf8.charCodeAt(str, 0) == 0x3042;
+haxe.Utf8.charCodeAt(str, 1) == 0xE9;
+haxe.Utf8.charCodeAt(str, 2) == 0x3044;
+var buf = new haxe.Utf8();
+buf.addChar(0x3042);
+buf.addChar(0xE9);
+buf.addChar(0x3044);
+buf.toString() == str;
+haxe.Utf8.compare(haxe.Utf8.sub(str, 0, 3), str) == 0;
+haxe.Utf8.compare(haxe.Utf8.sub(str, 0, 2), "あé") == 0;
+haxe.Utf8.compare(haxe.Utf8.sub(str, 1, 2), "éい") == 0;
+haxe.Utf8.compare(haxe.Utf8.sub(str, 0, 0), "") == 0;
+haxe.Utf8.compare(haxe.Utf8.sub(str, 1, 0), "") == 0;
+haxe.Utf8.compare(haxe.Utf8.sub(str, 9, 0), "") == 0;