test stint more thoroughly (#24832)

Author: narimiran

testament/important_packages.nim

@@ -155,7 +155,7 @@ pkg "smtp", "nimble compileExample"
 pkg "snip", "nimble test", "https://github.com/genotrance/snip"
 pkg "ssostrings", "nim c -r tests/tssostrings.nim"
 pkg "stew"
-pkg "stint", "nim c stint.nim"
+pkg "stint", "nimble test_internal"
 pkg "strslice"
 pkg "strunicode", "nim c -r --mm:refc src/strunicode.nim"
 pkg "supersnappy"