some test cleanups & category reorganization (#22010)

* clean up some test categories

* mention exact slice issue

* magics into system

* move trangechecks into overflow

* move tmemory to system

* try fix CI

* try fix CI

* final CI fix

tests/effects/toutparam.nim

@@ -1,28 +0,0 @@
-discard """
-  cmd: '''nim c --warningAsError:Uninit:on --skipCfg --skipParentCfg $file'''
-  errormsg: "use explicit initialization of 'x' for clarity [Uninit]"
-  line: 24
-  disabled: "true"
-"""
-
-proc gah[T](x: out T) =
-  x = 3
-
-proc main =
-  var a: array[2, int]
-  var x: int
-  gah(x)
-  a[0] = 3
-  a[x] = 3
-  echo x
-
-main()
-
-proc mainB =
-  var a: array[2, int]
-  var x: int
-  a[0] = 3
-  a[x] = 3
-  echo x
-
-mainB()