Lotta of small dumpstate fixes...

- Fixed RunCommandToFd() so it respects DROP_ROOT.
- Renamed enums to be more consistent with fd model.
- Added tests to RunCommandToFd() and DumpFileToFd().
- Fixed RunCommandToFd() and DumpFileToFd(), which were rushed in.
- Disable tests that fail when running as suite.

BUG: 31982882
Test: manual verification
Test: dumpstate_tests pass

Change-Id: I1d8352a17be10a707a101fc1ac9c7d735e38f9fe