elf: Replace tst-audit24bmod2.so with tst-audit24bmod2

Replace tst-audit24bmod2.so with tst-audit24bmod2 to silence:

make[2]: Entering directory '/export/gnu/import/git/gitlab/x86-glibc/elf'
Makefile:2201: warning: overriding recipe for target '/export/build/gnu/tools-build/glibc-gitlab/build-x86_64-linux/elf/tst-audit24bmod2.so'
../Makerules:765: warning: ignoring old recipe for target '/export/build/gnu/tools-build/glibc-gitlab/build-x86_64-linux/elf/tst-audit24bmod2.so'

(cherry picked from commit fa7ad1df)