RFR: SieveObjects test is too hostile to verification

[Aleksey Shipilev]

http://cr.openjdk.java.net/~shade/shenandoah/tests-sieve-verify/webrev.01

SieveObjects allocates a lot of objects, retained from the single array. Verifier does not do array
chunking to keep itself simple, and thus verification for this test takes a while. Since
verification costs are dependent on the number of objects, but test itself maintains the ragged
array of decent footprint, the way out is to make the per-object footprint 10x larger, and thus trim
the number of objects 10x too.

Testing: SieveObjects

Thanks,
-Aleksey