sgx_config_cpusvn is ignored by the simulated EGETKEY

If no CPUSVN is specified in the `sgx_key_request_t` structure then `sgx_get_key` in simulation uses a hardcoded CPUSVN rather than the "upgraded" or "downgraded" SVN from the `sgx_config_cpusvn` tool.

It would look like the issue is in this line: https://github.com/intel/linux-sgx/blob/4589daddd58bec7367a6a9de3fe301e6de17671a/sdk/simulation/tinst/t_instructions.cpp#L143

Start at sdk/simulation/tinst/t_instructions.cpp near the referenced line and trace how simulated EGETKEY handles an absent CPUSVN in sgx_key_request_t. Compare that path with the upgraded or downgraded SVN configured by the sgx_config_cpusvn tool; done means the simulated sgx_get_key uses that configured value instead of a hardcoded CPUSVN.

Written by the indexing model from the issue text.