Make aligned_alloc match the standard.

Jemalloc does not verify that the size parameter is a multiple of
alignment. Fix this since it only went into P.

Fix the unit tests, and fix malloc debug/malloc hooks to handle this
new restrictive behavior.

Bug: 126944692

Test: Ran bionic unit tests.
Test: Ran bionic unit tests with malloc hooks enabled (no new tests fail).
Test: Ran bionic unit tests with malloc debug enabled (no new tests fail).
Test: Ran malloc debug unit tests.
Change-Id: I4d50785928815679c781ca729f998454d76b9192