Add test case for wide char handling in wide string literal

tests/tests2/97_utf8_string_literal.c

@@ -0,0 +1,12 @@
+// this file contains BMP chars encoded in UTF-8
+#include <stdio.h>
+#include <wchar.h>
+
+int main()
+{
+    wchar_t s[] = L"hello$$你好¢¢世界€€world";
+    wchar_t *p;
+    for (p = s; *p; p++) printf("%04X ", (unsigned) *p);
+    printf("\n");
+    return 0;
+}

tests/tests2/97_utf8_string_literal.expect

@@ -0,0 +1 @@
+0068 0065 006C 006C 006F 0024 0024 4F60 597D 00A2 00A2 4E16 754C 20AC 20AC 0077 006F 0072 006C 0064