Allow empty mini-debug-info ELF section.

Generate mini-debug-info ELF section even if it is empty
(if we generate oat file with no compiled methods).

The intention is to make it easier to distinguish ELF files
miss the section unintentionally due to build configuration.

The overhead of the empty section is 140 bytes per oat file.

Bug: 37724669
Test: test.py -b -r -t 137
Change-Id: I521da6bb1a04d099465a3ffd9e05b7c836165208
2 files changed