Renamed HsumBootUserInitializerTest to HsumBootUserInitializerInitMethodTest

This change will allow the "real" HsumBootUserInitializerTest be used
for tests that don't require parameters.

Bug: 402486365
Test: atest FrameworksMockingServicesTests --test-filter=".*HsumBootUserInitializerInitMethodTest.*"
Flag: TEST_ONLY

Change-Id: I866d20b9356976e922168e41968a1a8dd56189f9