[ARM] Make empty name symbols SF_FormatSpecific to try appeasing...

[ARM] Make empty name symbols SF_FormatSpecific to try appeasing --target=armv7-linux-androideabi24 sanitizer symbolization tests

This is similar to D98669 but I don't know whether and why ARM needs it.

I suspect this may fix the sanitizer-x86_64-linux-android bot which runs
--target=armv7-linux-androideabi24 tests
(https://lab.llvm.org/buildbot/#/builders/77)

Someone needs to investigate the root cause and I am not sure this hack
fixes the bot.