Summary:
This commit augments codes to clean up temporary files generated by the clang frontend.
Currently clang frontend leaves large number of temporary files int the tmp directory, and it could be seen for example by running these command:
```
git clean -xdf infer/models/
mkdir /tmp/infer
env TMPDIR=/tmp/infer make infer_models
ls -l /tmp/infer
```
P.S. Analyzing real project could easily cause each infer capture to leave hundreds of files in /tmp
P.P.S. There are 11 total references to Filename.temp_file however, other 9 seems don't leak temporary files in such large scale (at least not when using the clang frontend).
Closes https://github.com/facebook/infer/pull/816
Reviewed By: jvillard
Differential Revision: D6385311
Pulled By: dulmarod
fbshipit-source-id: f7956b0
Vladimir Silyaev