The patch fixes Function Multi Versioning features detection by ifunc resolver on Android API levels < 30.
Ifunc hwcaps parameters are not supported on Android API levels 23-29,
so all CPU features are set unsupported if they were not initialized
before ifunc resolver call.
There is no support for ifunc on Android API levels < 23, so Function
Multi Versioning is disabled in this case.
Also use two underscore prefix for FMV runtime support functions to
avoid conflict with user program ones.