Remove duplicated code in test/Metadata

test/Metadata.h

@@ -31,6 +31,7 @@ namespace test
 bytes bytecodeSansMetadata(bytes const& _bytecode);
 
 /// Returns the bytecode with the metadata hash stripped out.
+/// Throws exception on invalid hex string.
 std::string bytecodeSansMetadata(std::string const& _bytecode);
 
 /// Expects a serialised metadata JSON and returns true if the