Fix initrand to avoid random number sequences overlapping (#18744)

* Fix initrand to avoid random number sequences overlapping

* Minor fix

* Fix compile error on js backend

* Disable new test for js backend

* Minor fix

* tempfiles module uses random.initRand()

* Remove unused module import from lib/std/tempfiles.nim

* Initialize baseState in initRand()

* Run tests/stdlib/trandom.nim from tests/test_nimscript.nims

* baseState is initialized only with sysrand.urandom and quit if failed

* Add comments

tests/test_nimscript.nims

@@ -71,6 +71,8 @@ import std/[
   decls, compilesettings, with, wrapnils
 ]
 
+import stdlib/trandom
+
 echo "Nimscript imports are successful."
 
 block: