[markdown-report] restore the test suite of the plug-in

src/plugins/markdown-report/tests/md/cwe126.c

src/plugins/markdown-report/tests/md/oracle/cwe126.0.md

...plugins/markdown-report/tests/md/oracle/cwe126.res.oracle

src/plugins/markdown-report/tests/md/test_config

src/plugins/markdown-report/tests/ptests_config

src/plugins/markdown-report/tests/sarif/cwe125.c

src/plugins/markdown-report/tests/sarif/libc.c

...gins/markdown-report/tests/sarif/oracle/cwe125.res.oracle

...gins/markdown-report/tests/sarif/oracle/libc.0.res.oracle

...gins/markdown-report/tests/sarif/oracle/libc.1.res.oracle

...lugins/markdown-report/tests/sarif/oracle/with-libc.sarif

...ins/markdown-report/tests/sarif/oracle/without-libc.sarif