ARROW-7355: [CI] Environment variables are defined twice for the fuzzit builds
ARROW-7355: [CI] Environment variables are defined twice for the fuzzit builds

Closes #5996 from kszucs/ARROW-7355 and squashes the following commits:

b6c1fe7ba <Krisztián Szűcs> Merge the environment variables

Authored-by: Krisztián Szűcs <6bab32dc957a05a87930e779f272342e159326fa@gmail.com>
Signed-off-by: Sutou Kouhei <73218711cdd5d5c30ac66da3cc4d9d9204caf34b@clear-code.com>

kou/arrow,laurentgo/arrow,wesm/arrow,cpcloud/arrow,xhochy/arrow,xhochy/arrow,apache/arrow,laurentgo/arrow,apache/arrow,kou/arrow,xhochy/arrow,laurentgo/arrow,xhochy/arrow,laurentgo/arrow,xhochy/arrow,laurentgo/arrow,cpcloud/arrow,kou/arrow,icexelloss/arrow,icexelloss/arrow,icexelloss/arrow,wesm/arrow,laurentgo/arrow,kou/arrow,xhochy/arrow,kou/arrow,apache/arrow,icexelloss/arrow,cpcloud/arrow,kou/arrow,xhochy/arrow,cpcloud/arrow,apache/arrow,wesm/arrow,xhochy/arrow,wesm/arrow,xhochy/arrow,icexelloss/arrow,cpcloud/arrow,apache/arrow,icexelloss/arrow,icexelloss/arrow,xhochy/arrow,xhochy/arrow,icexelloss/arrow,apache/arrow,wesm/arrow,laurentgo/arrow,wesm/arrow,icexelloss/arrow,apache/arrow,kou/arrow,cpcloud/arrow,laurentgo/arrow,apache/arrow,kou/arrow,wesm/arrow,kou/arrow,cpcloud/arrow,kou/arrow,xhochy/arrow,apache/arrow,apache/arrow,cpcloud/arrow,kou/arrow,apache/arrow,wesm/arrow,kou/arrow,cpcloud/arrow,cpcloud/arrow,wesm/arrow,icexelloss/arrow,wesm/arrow,xhochy/arrow,wesm/arrow,apache/arrow,cpcloud/arrow,laurentgo/arrow,laurentgo/arrow,wesm/arrow,wesm/arrow,xhochy/arrow,xhochy/arrow,laurentgo/arrow,kou/arrow,apache/arrow,cpcloud/arrow,laurentgo/arrow,icexelloss/arrow,cpcloud/arrow,apache/arrow,wesm/arrow,cpcloud/arrow,kou/arrow,laurentgo/arrow,icexelloss/arrow,laurentgo/arrow,icexelloss/arrow,laurentgo/arrow,icexelloss/arrow