RSA CRT requires public exponent starting with 1.77 for raw RSA operation

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While updating BC in OpenSCDP we see raw RSA operations fail with private keys in CRT format.

Starting with 1.77 a NPE 'Cannot read field "signum" because "exponent" is null' is thrown if no
public exponent in present in the CRT structure.

I suspect that c62e5d0 is causing this. The code seems to check if a public exponent is present, but maybe there is a check missing.