Defrag: fix test false positive.

Apparently 1.4 is too low compared to what you get in certain setups
(including mine). I raised it to 1.55 that hopefully is still enough to
test that the fragmentation went down from 1.7 but without incurring in
issues, however the test setup may be still fragile so certain times this
may lead to false positives again, it's hard to test for these things
in a determinsitic way.

Related to #3786.

tests/unit/memefficiency.tcl

@@ -38,7 +38,7 @@ start_server {tags {"memefficiency"}} {
 
 start_server {tags {"defrag"}} {
     if {[string match {*jemalloc*} [s mem_allocator]]} {
-        test "Actove defrag" {
+        test "Active defrag" {
             r config set activedefrag no
             r config set active-defrag-threshold-lower 5
             r config set active-defrag-ignore-bytes 2mb
@@ -70,9 +70,10 @@ start_server {tags {"defrag"}} {
             # instead we currently look at RSS so we need to ask for purge
             r memory purge
 
-            # test the the fragmentation is lower and that the defragger stopped working
+            # Test the the fragmentation is lower and that the defragger
+            # stopped working
             set frag [s mem_fragmentation_ratio]
-            assert {$frag < 1.4}
+            assert {$frag < 1.55}
             set misses [s active_defrag_misses]
             after 500
             set misses2 [s active_defrag_misses]