Set TF OSS flags in bazelrc

Tensorflow unconditionally sets these flags in their bazelrc and uses them to control some dependencies. A usage of these just showed up in some dependency we transitively include through the tensorflow python monolithic target in tensorflow/tensorflow@de51a99, so now we get errors about not finding dependencies (https://source.cloud.google.com/results/invocations/b6432bad-9c55-4911-b6b3-755e1c87e73c/targets).

I would love to not have to pollute our bazelrc with TF weirdness, but this is yet another case of TF making itself unusable as a library and I don't see a lot of other options.

PiperOrigin-RevId: 319267814

.bazelrc

@@ -28,6 +28,11 @@ common --experimental_repo_remote_exec
 # Actually printing output on errors is... a useful default
 test --test_output=errors
 
+# TensorFlow always sets these in OSS which makes it impossible to build TF
+# without them...
+build --define open_source_build=true
+test --define open_source_build=true
+
 ###############################################################################
 # Options for "generic_clang" builds: these options should generally apply to
 # either clang or gcc and are curated based on need.