Don't use tf 1.15.1 in tests (#3289)

test_constraints_max_tf1_version.txt

 # For projects with upper bounds, we should periodically update this list to the latest release version
 grpcio>=1.23.0
 numpy>=1.17.2
-tensorflow>=1.14.0,<2.0
+# Temporary workaround for https://github.com/tensorflow/tensorflow/issues/36179 and https://github.com/tensorflow/tensorflow/issues/36188
+tensorflow>=1.14.0,<1.15.1
 h5py>=2.10.0