Fix metrics in GC performance dump

The mean GC throughput and total bytes freed metrics were not consistent with
the corresponding metrics of the individual collectors. The issue was
that the large objects were not taken into consideration in one case.

Bug: b/129707841
Test: art/test/testrunner/testrunner.py --host --runtime-option=-XX:DumpGCPerformanceOnShutdown
Change-Id: I26deb1b3a3ac7de84412b30514efd4447d4f3945
2 files changed