Replace Reference StandardCompiler.cpp

[dizer-ti]

Hey team—noticed a dead link, replaced it with a working URL

http://github.com/ethereum/solidity/std/StandardToken.sol - error
https://github.com/ethereum/solidity/blob/develop/test/compilationTests/gnosis/Tokens/StandardToken.sol - new link

[github-actions]

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[matheusaaguiar]

I don't think it matters for the tests that the urls are dead, but it also doesn't harm to have them working.