Disable optimizers for OpTester operator unit tests (#2237)
* Disable optimizers for operator unit tests as they're intended to test the operator directly rather than something that could have been modified by an optimizer.
Disable TensorRT for Scan9 unit tests that fails when optimizers are enabled. Bug 525222 tracks that.
* Disable TRT for the lenient shape inferencing test as it uses Unsqueeze and TRT doesn't cope with that op.
