android.hardware.graphics.allocator@2.0 is no longer VNDK-SP

The interface lib has been in VNDK-SP because
android.hardware.graphics.mapper@1.0 was using it. However, since the
dependency has gone [1], there is no need keep it in VNDK-SP. The
VNDK-SP set should be kept as small as possible because libs in VNDK-SP
are subject to double-loading.

Unmark the 'support_system_process' property to exclude the lib from
VNDK-SP.

This commit re-lands I8722c1ac15ddf56a627a12a0c649b4d734e5e5cd because
it was reverted during O-MR1 push to AOSP-master.

Bug: 69480083
Test: walleye boots to the UI
Change-Id: I0af8115dceb9711c6c451ffaeedda6c823ec2905
Merged-In: I8722c1ac15ddf56a627a12a0c649b4d734e5e5cd
(cherry picked from commit ec44d18d)