Intentionally suspended e10s tab cannot be restored on the next startup

[piroor]

Tested on Nightly 47.0a1 with e10s.

When there are some tabs which are suspended by this addon, then those tabs are not restored correcty after restart.
Errors in the console:

Error: Given tab is not pending. SessionStore.jsm:3356:13

[piroor]

Steps to reproduce:

1. Go to about:config and activate e10s with two preferences:
   • extensions.e10sBlocksEnabling=false
   • extensions.e10sBlockedByAddons=false
2. Configure Firefox to restore last tabs on the next startup.
3. Activate Suspend Tab.
4. Activate "Suspend tabs older than xxx tabs..." feature.
5. Open some remote tabs (webpage tabs).
6. Suspend those remote tabs with the limit.
7. Restart Firefox.
8. Click one of remote tabs which is suspended at 5.

Expected result: The clicked tab is restored correctly.

Actual result: The clicked tab does not restored. It still has "pending" attribute, but "about:blank" URL with empty session history. Unreloadable, unrestorable.

[piroor]

Maybe fixed.