Merge pull request #19007 from asutherland/email-virt-list-slice-fix

Bug 1004137 - [email] Absolute positioned virtual list regression: Refresh-synced folder not showing newly added message outside date range. r=jrburke. a=1.4+
Merge pull request #19010 from asutherland/v1.4-virt-list-slice-fix

Bug 1004137 - [email] Absolute positioned virtual list regression: Refresh-synced folder not showing newly added message outside date range. r=jrburke. a=1.4+