Attempt to fix the intermittent test failures with nREPL on macos. (#825)

Hi,

could you please review patch to attempt to fix the intermittent
failures of the nrepl server cli test on macos. It fixes #824.

It seems that the server has not been given the chance to write the port
number to the newly created file, so it attempts to yield control back
to the server.

Thanks

Co-authored-by: ikappaki <[email protected]>

Author: ikappaki

tests/basilisp/cli_test.py

@@ -159,7 +159,7 @@ def test_run_nrepl(self, run_cli):
             # the high retries number is to address the slowness when
             # running on pypy.
             retries = 60
-            while not os.path.exists(tmpfilepath):
+            while not os.path.exists(tmpfilepath) or os.stat(tmpfilepath).st_size == 0:
                 time.sleep(1)
                 retries -= 1
                 assert 0 <= retries