Add failing ORC thread-safety regressions and run all suites with nimble test

tests/writer_child.nim

@@ -0,0 +1,29 @@
+import std/os
+import ../src/namespaced_logging
+
+when not defined(multithreaded):
+  {.error: "Compile this fixture with -d:multithreaded to exercise writer threads".}
+
+proc formatLine(msg: LogMessage): string {.gcsafe.} = msg.msg & "\n"
+
+proc main() =
+  doAssert paramCount() == 2
+  var service = initLogService()
+  case paramStr(1)
+  of "file":
+    service.addAppender(initFileLogAppender(paramStr(2)))
+  of "console":
+    # Keep stdout open through the library's exit hook. Redirecting it to a
+    # file also prevents a full parent/child pipe from blocking the writer.
+    doAssert open(stdout, paramStr(2), fmWrite)
+    service.addAppender(initConsoleLogAppender(formatter = formatLine))
+  else:
+    raise newException(ValueError, "unknown writer destination")
+
+  let local = service.threadLocalRef()
+  let logger = local.getLogger("shutdown")
+  for i in 0 ..< 10_000:
+    logger.info("message " & $i)
+  # No sleep or explicit flush: normal exit must preserve accepted messages.
+
+main()