fix #16256: nimout: <empty> should give error (vacuously true); improve a few tests (#18089)

* fix #16256: nimout: <empty> should give error (vacuously true); improve some tests

* renamed:    tests/stdlib/t9710.nim -> tests/misc/t9710.nim

* improve tests

* fix non-DRY tests

* improve $nim_prs_D/tests/stdlib/t9091.nim

* renamed:    tests/stdlib/t9091.nim -> tests/misc/t9091.nim

* fixup

* address comment: doAssert => result.parseErrors

tests/stdlib/tgetprotobyname.nim

@@ -1,15 +1,5 @@
-discard """
-  cmd:      "nim c -r --styleCheck:hint --panics:on $options $file"
-  targets:  "c"
-  nimout:   ""
-  action:   "run"
-  exitcode: 0
-  timeout:  60.0
-"""
-
 import nativesockets
 
-
 when not defined(netbsd):
   # Ref: https://github.com/nim-lang/Nim/issues/15452 - NetBSD doesn't define an `ip` protocol
   doAssert getProtoByName("ip") == 0