Merge tests into a larger file (part 5 of ∞) (#9368)

* merge magics

* merge metatype tests

* merge method tests

* merge objects tests

* change `import future` to `import sugar`

Nim in Action tests are left with `import future`, to ensure compatibility.

* merge overload tests

* merge proc tests

* merge procvar tests

* merge range tests

* merge seq tests

* merge sets tests

* remove wrong assert from `tsets3`

* fix `jsTests`

* better fix

tests/concepts/trandom_vars.nim

@@ -30,7 +30,7 @@ proc map[A, B](x: RandomVar[A], f: proc(a: A): B): ClosureVar[B] =
 
   result.f = inner
 
-import future
+import sugar
 
 proc fakeRandom(): Random =
   result.random = () => 0.5