bisect tool: Symbolic link re-generated bad item to original one

This patch modifies the way to genearte bad item while pass level
bisection. Rather than directly overwrite the old object, we generate it
to a tmp file and symblic link it to original one to satisfy building
tool.

BUG=chromium:878954
TEST=Ran test successfully with Android compiler wrapper.

Change-Id: If152742e0a2088e9d8c2456bf046cede938d88d3
Reviewed-on: https://chromium-review.googlesource.com/1220016


Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Zhizhou Yang <zhizhouy@google.com>
Reviewed-by: Caroline Tice <cmtice@chromium.org>