Only clear system_shared_libs when building for bionic am: 74985fcc am:...

Only clear system_shared_libs when building for bionic am: 74985fcc am: 293b5a5b am: c4df296a am: 7621d770

Original change: https://android-review.googlesource.com/c/platform/external/arm-optimized-routines/+/1968802

Change-Id: I9174171f2ae0726057235d73e2a173a7aa2a04c6