fix tests

Author: timotheecour

lib/pure/collections/sets.nim

@@ -1020,7 +1020,7 @@ when isMainModule and not defined(release):
 
     block toSeqAndString:
       var a = toHashSet([2, 7, 5])
-      var b = initHashSet[int]()
+      var b = initHashSet[int](rightSize(a.len))
       for x in [2, 7, 5]: b.incl(x)
       assert($a == $b)
       #echo a

lib/pure/hashes.nim

@@ -91,7 +91,7 @@ proc hashData*(data: pointer, size: int): Hash =
 
 proc hashBiggestIntVM(x: BiggestInt): Hash = discard # in vmops
 
-proc hash*(x: string): Hash
+proc hash*(x: string): Hash {.noSideEffect.}
 
 proc hashBiggestInt*(x: BiggestInt): Hash {.inline.} =
   ## for internal use; user code should prefer `hash` overloads