circleci: Revert recent changes

Going back to pretending 32bit bionic builds are fine until #3702 is
sorted out. We have 32bit coverage in our vtest CI anyway.

Reverts f8974400
Reverts c5ed00b6

.circleci/config.yml

@@ -365,7 +365,7 @@ workflows:
           name: distcheck_ubuntu_bionic
           dist: ubuntu
           release: bionic
-          extra_conf: CFLAGS=-g\ -O2\ -m32
+          extra_conf: CFLAGS='-g -O2 -m32'
       - distcheck:
           name: distcheck_alpine
           dist: alpine