Platform BpfLoader: remove IGNORE_ON_{USER,USERDEBUG,ENG} support

Unlike in mainline, this isn't actually particularly useful for
platform, as you can simply not include such programs
via Android.bp/mk stanzas at build time.

Even in mainline we've had only one user (and we've graduated
that use as well...)

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com
Change-Id: I66a83e79a866c306de4c409e8b5822eac99454ec