Oilpan: remove too strong start-of-heap-object assert.
Oilpan: remove too strong start-of-heap-object assert.

Remove the assert checking if willObjectBeLazilySwept()'s argument is a
valid reference to the start of a heap object payload. That's too strong
a requirement as the argument might be a mixin pointing some way into
the payload.

Any adjustment needed to get to the object header is taken care of by
isHeapObjectAlive(), which will also check the sanity of the object's
header. Hence, remove the check from willObjectBeLazilySwept().

TBR=oilpan-reviews,haraken
BUG=448392
NOTRY=true

Review URL: https://codereview.chromium.org/867623002

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@188812 bbb929c8-8fbe-4397-9dbb-9b2b20218538

XiaosongWei/blink-crosswalk,smishenk/blink-crosswalk,PeterWangIntel/blink-crosswalk,smishenk/blink-crosswalk,Pluto-tv/blink-crosswalk,smishenk/blink-crosswalk,kurli/blink-crosswalk,Pluto-tv/blink-crosswalk,kurli/blink-crosswalk,XiaosongWei/blink-crosswalk,XiaosongWei/blink-crosswalk,kurli/blink-crosswalk,smishenk/blink-crosswalk,XiaosongWei/blink-crosswalk,kurli/blink-crosswalk,kurli/blink-crosswalk,Pluto-tv/blink-crosswalk,smishenk/blink-crosswalk,kurli/blink-crosswalk,Bysmyyr/blink-crosswalk,smishenk/blink-crosswalk,PeterWangIntel/blink-crosswalk,XiaosongWei/blink-crosswalk,kurli/blink-crosswalk,PeterWangIntel/blink-crosswalk,kurli/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,kurli/blink-crosswalk,Pluto-tv/blink-crosswalk,Bysmyyr/blink-crosswalk,XiaosongWei/blink-crosswalk,kurli/blink-crosswalk,Pluto-tv/blink-crosswalk,smishenk/blink-crosswalk,Bysmyyr/blink-crosswalk,Bysmyyr/blink-crosswalk,PeterWangIntel/blink-crosswalk,Bysmyyr/blink-crosswalk,PeterWangIntel/blink-crosswalk,Pluto-tv/blink-crosswalk,PeterWangIntel/blink-crosswalk,smishenk/blink-crosswalk,XiaosongWei/blink-crosswalk,Bysmyyr/blink-crosswalk,XiaosongWei/blink-crosswalk,Bysmyyr/blink-crosswalk,PeterWangIntel/blink-crosswalk,XiaosongWei/blink-crosswalk,Bysmyyr/blink-crosswalk,Bysmyyr/blink-crosswalk,Pluto-tv/blink-crosswalk,Bysmyyr/blink-crosswalk,smishenk/blink-crosswalk,XiaosongWei/blink-crosswalk,PeterWangIntel/blink-crosswalk,Pluto-tv/blink-crosswalk,smishenk/blink-crosswalk,PeterWangIntel/blink-crosswalk,PeterWangIntel/blink-crosswalk