Do not request EVM bytecode outside test

[xermicus]

I noticed we always request the EVM bytecode from solc. We need it during tests and benchmarks. But it is unnecessary when compiling to PVM. This should be changed because emitting the bytecode is extra work in solc. Instead, the test utils should just request it explicitly and then resolc adds the EVM runtime and deploy codes to the standard JSON settings supplied to solc.