pgsql: Fix link error for test_radixtree module on Windows

Fix link error for test_radixtree module on Windows

Add back "link_with" directive, similar to the one removed by 1f1d73a8b,
but only for Windows, but use the "_shlib" variation.

Diagnosis by Masahiko Sawada, proposed fix adjusted and tested by me

Per buildfarm members drongo and fairywren

Discussion: https://postgr.es/m/CAD21AoAMm1mQd%3Dw4PrfrKK%3DOMP8j8%3D7ntJRPF8%2B%3D10iUuvwiCA%40mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/9552e3ace317ac8bb0a80613c0e5cd6536c96dc8

Modified Files
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src/test/modules/test_radixtree/meson.build | 1 +
1 file changed, 1 insertion(+)