StreamTest no longer needs the HostIrLowering knob. (#5748)

Author: wujingyue

tests/cpp/test_stream.cpp

@@ -24,12 +24,10 @@
 
 namespace nvfuser {
 
-class StreamTest : public NVFuserTest {
- public:
-  StreamTest() {
-    EnableOptionsGuard::getCurOptions().set(EnableOption::HostIrLowering);
-  }
-};
+// The tests in this file verify building blocks for stream parallelism, e.g.,
+// sharding propagation and KernelExecutor. End-to-end tests have been moved to
+// tests/python/direct/test_stream.py because the Python API is sufficient.
+using StreamTest = NVFuserTest;
 
 TEST_F(StreamTest, AddPerStream) {
   constexpr int64_t c = 3;