Short-circuit for side-effecting (IO) ops

[spurserh]

To add:

TEST_F(TranslatorTest, IOShortCircuitAnd) { const std::string content = R"( #include "/xls_builtin.h" #pragma hls_top void my_package(__xls_channel& in, __xls_channel& out) { const int zero = 0; int v = 100; v = zero && in.read(); out.write(1 + v); })";

IOTest(content, /inputs=/{}, /outputs=/{IOOpTest("out", 101, true)}); }

[spurserh]

This may actually be a bug when it comes to assignments in short-circuit expressions.