16k: core: Update PRODUCT_PAGE_SIZE_AGNOSTIC to PRODUCT_NO_BIONIC_PAGE_SIZE_MACRO

This is to help clarify that this flag doesn't mean the device
will actually work end-to-end with any page size. Renaming
several dependent variables will be done in subsequent patches.

Bug: 312541564
Test:
```
 $ source build/envsetup.sh
 $ lunch aosp_cf_arm64_phone_pgagnostic-trunk-userdebug
 $ get_build_var TARGET_NO_BIONIC_PAGE_SIZE_MACRO
 true
```
Change-Id: I9bae8b00139f601a3324da902aeb4ae82113ccdd