Set Mark-bit for large Zygote objects

We set the mark-bit of Zygote objects before forking to ensure that the
objects are not dirtied due to GC trying to modify the GC related bits
in the objects' header. The same was mistakenly not being done for
large-space objects corresponding to Zygote.

Test: art/test/testrunner/testrunner.py --target --64
Bug: 37254935
Change-Id: I173d6090a6ec0fd7e511e1d684341ecf0968e97f
3 files changed