Update the avd path in ini during install.

Behavior in newer emulator versions changes so that it looks for the
system image from the `path` value of root_ini file. So let's update
that value so that emulator can run without error.

Also add `time` debug tag to default start and create process to make
the log more informative (Note `time` tag is added on Oct 2020 so won't take effect for older emulator versions).

Change-Id: I3c5ef9616196c95b95dc09bc28c68c172cc9e178
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3995362
Reviewed-by: Benjamin Joyce (Ben) <bjoyce@chromium.org>
Commit-Queue: Haiyang Pan <hypan@google.com>
Cr-Commit-Position: refs/heads/main@{#1066133}