Use std::string for profile operations instead of const char

Will make things cleaner when adding secondary dex profile support.

Also, add tests to verify profile path creation.

Bug: 26719109
Test: /data/nativetest64/installd_utils_test/installd_utils_test
Change-Id: I8cb1a11cefee21f5001d2b729110696d52fc8323
6 files changed