[BugFix] [Build] Fix for where setup.py fails with MAX_JOBS invalid literal error (#45188)

Signed-off-by: Randall Smith <Randall.Smith@amd.com>
Co-authored-by: Micah Williamson <micah.williamson@amd.com>

setup.py

@@ -216,7 +216,7 @@ class cmake_build_ext(build_ext):
         # `num_jobs` is either the value of the MAX_JOBS environment variable
         # (if defined) or the number of CPUs available.
         num_jobs = envs.MAX_JOBS
-        if num_jobs is not None:
+        if isinstance(num_jobs, str) and num_jobs.isnumeric():
             num_jobs = int(num_jobs)
             logger.info("Using MAX_JOBS=%d as the number of jobs.", num_jobs)
         else: