[backend] Update python generation scripts

Update references to berberis. Use std namespace prefix for string. Use
using statements in place of typedefs. Use allowlist naming. Make
load_all_lir_defs and expand_aliases public so they can be used in the
using generators in ndk. Update license headers. Update arg parsing to
handle variable number of lir_instructions and machine ir bindings.

Bug: 291127204
Test: mm and berberis_host_tests
Change-Id: Ie7dd33432c570da2310f992408a633cf07035ab2
2 files changed