Revert "bionic_libc_platform_headers is only available when buil..."

Reason for revert: Breaks rvc-d1-dev-plus-aosp: http://ab/6443190
Reverted Changes:
Ide447b89a:bionic_libc_platform_headers is only available whe...
Ia93cd3ec8:bionic_libc_platform_headers is only available whe...
Icdc495588:Make bionic_platform_headers available only for Bi...
Idfd7c87dc:bionic_libc_platform_headers is only available whe...

Bug: 152255951
Bug: 155269399
Change-Id: I4e6beba5565e604fde3a51cdce5cc4041caffa4e