Consider CGO option when calculating binary hash

[pablochacin]

The build service cache is insensitive to CGO_ENABLED changes. It can be reproduced if we set CGO_ENABLED to 0 and then build, then set it to 1 and build again. Returns the previously built binary from the cache.

[pablochacin]

The main issue for addressing this information is not available when calculating the hash to use it as a key to check the cache.

The CGO_ENABLED flag is set in the k6foundry's builder, but it's not currently exposed.

If the builder exposed it, the build service could consider it as part of the hash.