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/generics/mfriends.nim

@@ -0,0 +1,11 @@
+
+type
+  TMyObj = object
+    x: int
+
+proc gen*[T](): T =
+  var d: TMyObj
+  # access private field here
+  d.x = 3
+  result = d.x
+

tests/generics/tconstraints.nim

@@ -0,0 +1,16 @@
+discard """
+  errormsg: "type mismatch: got <int literal(232)>"
+  line: 16
+"""
+
+proc myGenericProc[T: object|tuple|ptr|ref|distinct](x: T): string =
+  result = $x
+
+type
+  TMyObj = tuple[x, y: int]
+
+var
+  x: TMyObj
+
+assert myGenericProc(x) == "(x: 0, y: 0)"
+assert myGenericProc(232) == "232"

tests/generics/tfriends.nim

@@ -0,0 +1,11 @@
+discard """
+  output: "3"
+"""
+
+# Tests that a generic instantiation from a different module may access
+# private object fields:
+
+import mfriends
+
+echo gen[int]()
+

tests/generics/toverloading_typedesc.nim

@@ -1,7 +1,3 @@
-discard """
-  exitcode: 0
-  disabled: '''true'''
-"""
 import moverloading_typedesc
 import tables
 
@@ -9,7 +5,6 @@ type
   LFoo = object
   LBar = object
 
-
 when true:
   doAssert FBar.new() == 3