Stop using BCryptGetFipsAlgorithmMode

[qmuntal]

We use BCryptGetFipsAlgorithmMode to know if Windows is running on FIPS mode.

The Windows team has informed us that that function is deprecated (although the docs still don't say that) and shouldn't be used. Windows is always FIPS compliant regardless of what that functions says.

We should treat Windows in the same way as we treat Darwin with respect to FIPS mode:

• Windows is always FIPS compliant, so running with GODEBUG=fips140=on should always succeed regardless of BCryptGetFipsAlgorithmMode.
• fips140.Enabled should not take into account the system-wide configuration.