A64: tidy up the disassembler

R=ulan@chromium.org

Review URL: https://codereview.chromium.org/171603020

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@19727 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
AllocationTracker now maintains a map from address range to stack trace that allocated the range. When snapshot is generated the map is used to find construction stack trace for an object using its address.

BUG=chromium:277984
LOG=Y
R=alph@chromium.org, mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/177983003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@19728 ce2b1a6d-e550-0410-aec6-3dcde31c8c00