Testing framework improvement

[acquamarin]

The getInputDir() assumes the path ends with a '/'. If the path doesn't end with '/', incorrect schema.cypher, copy.cypher path will be generated.

class test1 : public DBTest {
public:
    std::string getInputDir() override { return "dataset/tinysnb-serial"; }
};

Tries to find the following cypher scripts:

cypherScript: dataset/tinysnb-serialschema.cypher
CpyherScript: dataset/tinysnb-serialschema.cypher doesn't exist. Skipping...
cypherScript: dataset/tinysnb-serialcopy.cypher
CpyherScript: dataset/tinysnb-serialcopy.cypher doesn't exist. Skipping...