Move system_shared_libs into target.bionic clause

Use target.bionic.system_shared_libs when it is used to limit the
default shared libraries (as opposed to remove them completely).
This avoids attempting to add a host dependency on libc when
system_shared_libs is modified to apply to all variants.

Bug: 193559105
Test: m checkbuild
Change-Id: I6cf8e90424431b5abb8ddb32dbf7dfd7a4b8570a
1 file changed