Revert PR #438 with shortened SHA test vector (#463)

The fix from PR #438 is unnecessary because the failure scenario is already accounted for by a previous fix (38053da) that uses a C macro/preprocessor conditional to select an appropriate test vector for the sha accel smoke test based on the Caliptra configuration (Core vs Seed). Leaving a large vector in place is advantageous for testing the Core mode to ensure large messages work as expected, though the short vector is required for the Seed smoke test in order to compile the code.