Enable some E2E tests for CUDA (#4998)

Those are disabled by default in CI until a CUDA system is setup.
diff --git a/build_tools/cmake/test.sh b/build_tools/cmake/test.sh
index b38df1c..dc3ab5c 100755
--- a/build_tools/cmake/test.sh
+++ b/build_tools/cmake/test.sh
@@ -28,6 +28,8 @@
 # and turning on the llvmaot ones.
 export IREE_VULKAN_DISABLE=${IREE_VULKAN_DISABLE:-0}
 export IREE_LLVMAOT_DISABLE=${IREE_LLVMAOT_DISABLE:-0}
+# CUDA is off by default.
+export IREE_CUDA_DISABLE=${IREE_CUDA_DISABLE:-1}
 
 # Tests to exclude by label. In addition to any custom labels (which are carried
 # over from Bazel tags), every test should be labeled with the directory it is
@@ -57,6 +59,9 @@
 if [[ "${IREE_LLVMAOT_DISABLE?}" == 1 ]]; then
   label_exclude_args+=("^driver=dylib$")
 fi
+if [[ "${IREE_CUDA_DISABLE?}" == 1 ]]; then
+  label_exclude_args+=("^driver=cuda$")
+fi
 
 # Join on "|"
 label_exclude_regex="($(IFS="|" ; echo "${label_exclude_args[*]?}"))"