Disabling NVFUSER by default

Due to nvfuser issues on gfx908 causing the CudaFuser softmax UTs to fail it has been disabled by default

Author: jataylo

.jenkins/pytorch/common.sh

@@ -30,6 +30,9 @@ trap_add cleanup EXIT
 # shellcheck disable=SC2034
 BUILD_TEST_LIBTORCH=0
 
+# TODO: Reenable nvfuser when issues with gfx908 resolved
+PYTORCH_JIT_ENABLE_NVFUSER=0
+
 # Use conda cmake in some CI build. Conda cmake will be newer than our supported
 # min version (3.5 for xenial and 3.10 for bionic),
 # so we only do it in four builds that we know should use conda.