Set hashtree algorithm for verity partitions

This is used in cts tests to verify that algorithms in blocklist aren't
used to build the hashtree. The system properties are required to perform
the check on unrooted devices.

Bug: 175236047
Test: flash, getprop; atest CtsNativeVerifiedBootTestCases

Change-Id: I2dcfdb06f85dbe92cde45e836dd68e7bd835020f