[PyTorchEdge] Extend flatbuffer to support extra files map (#72951)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/72951
Extend flatbuffer to support extra files map
Flatbuffer schema has extra files. The users can write extra files by providing a `map<string, string>` which will be part of the flatbuffer model asset and and can be loaded back similar to pickle.
ghstack-source-id: 149622799
Test Plan:
fb:
```[pavithran@devvm5216.vll0 ~/fbsource/fbcode] cd ~/fbsource/fbcode/ && buck test caffe2/test/cpp/jit:jit -- FlatbufferTest.ExtraFiles
Parsing buck files: finished in 0.7 sec
Downloaded 0/8 artifacts, 0.00 bytes, 100.0% cache miss (for updated rules)
Building: finished in 20.0 sec (100%) 22343/22343 jobs, 4/22343 updated
Total time: 20.7 sec
More details at https://www.internalfb.com/intern/buck/build/7dba5034-d623-4a1e-afa1-b0e809df7066
BUILD SUCCEEDED
Tpx test run coordinator for Facebook. See https://fburl.com/tpx for details.
Running with tpx session id: 9c1ac1e0-a8c0-4a62-95df-8f49695aa7d1
Trace available for this run at /tmp/tpx-20220216-144630.207992/trace.log
RemoteExecution session id: reSessionID-9c1ac1e0-a8c0-4a62-95df-8f49695aa7d1-tpx
Started reporting to test run: https://www.internalfb.com/intern/testinfra/testrun/7318349470518809
✓ ListingSuccess: caffe2/test/cpp/jit:jit : 468 tests discovered (17.211)
✓ Pass: caffe2/test/cpp/jit:jit - FlatbufferTest.ExtraFiles (0.169)
Summary
Pass: 1
ListingSuccess: 1
If you need help understanding your runs, please follow the wiki: https://fburl.com/posting_in_tpx_users
Finished test run: https://www.internalfb.com/intern/testinfra/testrun/7318349470518809````
Reviewed By: iseeyuan
Differential Revision: D34286346
fbshipit-source-id: 4e09ab25b8ed6af6f8923db3aab046c255f13bb8
(cherry picked from commit ce8d88e22a360b25253d8a75f428d523fa88a79a)