builders.sh: Fix duplicity of `test` vs `[`.

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: Ifb1fdb168e3eeb3fa6b2d42663d4e21444763f1f
diff --git a/misra-docker-images/builders.sh b/misra-docker-images/builders.sh
index 1a607e8..777c1e6 100644
--- a/misra-docker-images/builders.sh
+++ b/misra-docker-images/builders.sh
@@ -23,7 +23,7 @@
 
 for image in ./*
 do
-    test [ -d $image ] && test [ -f $image/build.sh ] && \
+    test -d $image  && test -f $image/build.sh && \
     (
         set -ex
         echo "Building image: misra:$${image}"