Optionally add debug symbols to ELF files made by quick compiler.

Added debug symbols to ELF files created by dex2oat using
the quick compiler. Adds two flags --include-debug-symbols and
--no-include-debug-symbols for dex2oat that control the inclusion of these
debug symbols. Debug info is added by default if kIsDebugBuild is true.

Fixed bug where Intel DWARF information would not correctly deal with
deduplicated code the binary.

Changed the portable compiler code path in dex2oat.cc so that symbols
will not be stripped when run with --include-debug-symbols.

Change-Id: Ia2eb2f654dedf0e5e8606f7744e05b8d14155fb1