Function residual

benchmark/exprModels/ResNetExpr.cpp:19–28

When we use MNNConverter to convert other resnet model to MNN model, {Conv + BN + Relu} will be converted and optimized to {Conv}

// When we use MNNConverter to convert other resnet model to MNN model,
// {Conv + BN + Relu} will be converted and optimized to {Conv}
static VARP residual(VARP x, INTS channels, int stride) {
    int inputChannel = x->getInfo()->dim[1], outputChannel = channels[1];
    auto y = _Conv(0.0f, 0.0f, x, {inputChannel, outputChannel}, {3, 3}, SAME, {stride, stride}, {1, 1}, 1);
    y = _Conv(0.0f, 0.0f, y, {outputChannel, outputChannel}, {3, 3}, SAME, {1, 1}, {1, 1}, 1);
    if (inputChannel != outputChannel || stride != 1) {
        x = _Conv(0.0f, 0.0f, x, {inputChannel, outputChannel}, {1, 1}, SAME, {stride, stride}, {1, 1}, 1);
    }
    y = _Add(x, y);
    return y;
}

static VARP residualBlock(VARP x, INTS channels, int stride, int number) {
    x = residual(x, {channels[0], channels[1]}, stride);