tests: add regression tests for another revrange edge case

These tests would've passed before ac0c12123743 and e441657b372b.
Inserting them to make sure that continues to be the case.

tests/test-glog.t

@@ -2116,5 +2116,10 b' issue3772'
      user:
      date:        Thu Jan 01 00:00:00 1970 +0000
   
+  $ hg glog -r null:null
+  o  changeset:   -1:000000000000
+     user:
+     date:        Thu Jan 01 00:00:00 1970 +0000
+  
 
   $ cd ..

tests/test-log.t

@@ -1304,5 +1304,10 b' issue3772: hg log -r :null showing revis'
   user:        
   date:        Thu Jan 01 00:00:00 1970 +0000
   
+  $ hg log -r null:null
+  changeset:   -1:000000000000
+  user:        
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  
 
   $ cd ..