symbol_inject: add step to codesign Mach-O binaries.

The adhoc codesign of Macho-O binaries is broken after symbol
injection. MacOS refuses to run the binaries unless we sign
them again.

Bug: 241493489
Test: build and run simpleperf_ndk64 on MacOS
Change-Id: I25ef5c6413bd97e1bfa0a4ec5d04eaefb6fea54c