backout 8b380feae2ae to align talos number prior to uplift next week (bug 1205249)

configure.in

@@ -7251,9 +7251,6 @@ if test -z "$MOZ_MEMORY"; then
   esac
 else
   AC_DEFINE(MOZ_MEMORY)
-  if test -n "$NIGHTLY_BUILD"; then
-    MOZ_JEMALLOC4=1
-  fi
   if test -n "$MOZ_JEMALLOC4"; then
     AC_DEFINE(MOZ_JEMALLOC4)
   fi