Special case OCSP GET queries that might be corrupted by Go's mux

[stevendpclark]

Description

Workaround an incompatibility between Go's HTTP mux and a standard
OCSP GET request that encodes in standard base64 and places that in the
URL. Go's mux will try to canonicalize path components by changing
repeated '/' into a single '/', which corrupts the base64 encoding of an
OCSP request.

TODO only if you're a HashiCorp employee

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[github-actions]

CI Results:
All Go tests succeeded! ✅