circleci: Only run the test suite on alpine

There appears to be a race condition with distcheck where test-suite.log
is removed and then another attempt at removing it fails:

    [...]
    test -z "test-suite.log" || rm -f test-suite.log
    rm -f libtool config.lt
    find . '(' -name '*.gcda' -o -name '*.gcda' ')' -exec rm '{}' ';'
    rm -f TAGS ID GTAGS GRTAGS GSYMS GPATH tags
    rm -f cscope.out cscope.in.out cscope.po.out cscope.files
    find: ./test-suite.log: No such file or directory
    [...]

It is unclear which find command is choking on test-suite.log, there
doesn't seem to be a make rule running find and targeting this file.
Could it be the find command listed in the output collecting file names
like test-suite.log and then failing to test it against the -name
filters after it got removed? That would be infortunate for a find
implementation.

Since alpine is not a platform we officially support, and after failing
numerous times to reproduce the link outside of the CI environment, a
simple make check is good enough and it will remove a lot of noise.

.circleci/config.yml

@@ -439,6 +439,7 @@ workflows:
           dist: alpine
           release: "latest"
           extra_conf: --without-contrib
+          make_target: check
       - build:
           name: build_archlinux
           dist: archlinux