Update MemoryHeapBase to avoid abort

MemoryHeapBase currently logs fatal on passing invalid flags.
Since we control flags combinations as compile time constants within an
enum, we can enforce that all the enum values pass valid flag combos in
order to remove the fatal flag checks.

This avoids aborts in fuzzers consuming the enum value. If a user passes
MEMFD_ALLOW_SEALING_FLAG without FORCE_MEMFD set (not possible if using
the enum values), then the flag is silently ignored.

Test: atest binderUnitTest
Bug: 224667194
Change-Id: Iab90c8b0926ac32f01bb1489bf954c136dd2953f