A go-fuzz target for the ParseEventLog function. It has been tested
with go-fuzz and go-fuzz + libFuzzer.
oss-fuzz requires a statically built fuzzer binary, so `gofuzz` build
tags are added to avoid building files that depend on go-tspi. A mock
tpm_other.go file is also included to satisfy the `platformTPM`
interface.
Currently the activation challenge lets a caller supply a source of
randomness other than crypto/rand, but it's not used in some places.
Plumb the source through the call chain.