add another expr/decl ambiguity test

From-SVN: r21827

gcc/testsuite/g++.old-deja/g++.brendan/parse5.C

+// Build don't link: 
+
+// this is marked as an expected error because it evidences an
+// ambiguity in the grammar between expressions and declarations.
+// when the parser's been cleaned up or rewritten, the error
+// marker can go away, since it'll no longer occur.
+
+class ptr8
+   {
+public:
+   ptr8(unsigned char *string,int len);
+   };
+
+template <unsigned int S>
+class buf
+   {
+public:
+   buf(const ptr8& aRef);
+   };
+
+int main()
+   {
+   unsigned  char b[3];
+   buf<3> b2(ptr8(&b[0],3)); // ERROR - 
+   }