Allow cc_object to use libc headers under the VNDK

Bionic headers aren't implicit when building with the VNDK, they're
exported from libc. So add libc to the shared libraries of a cc_object
if it wants the standard flags.

Removes a duplicate No_default_compiler_flags

Test: Add cc_object with vendor_available, build on aosp_arm64_ab (VNDK-enabled)
Change-Id: I9bfcd1e1a65de4edc597bd348b79d625ecae4f5e