fix cmd/tools/vtest.v build

This PR enables building them again with v2, by making vlib/sync/pool.v
single threaded for now, and by removing the use of generics till they
are fixed in v2.

vlib/sync/pool_test.v

@@ -1,10 +1,5 @@
 import sync
 import time
-import rand
-
-struct SResult {
-	s string
-}
 
 fn worker_s(p &sync.PoolProcessor, idx int, worker_id int) voidptr {
 	// TODO: this works, but confuses vfmt. It should be used instead of
@@ -12,12 +7,8 @@ fn worker_s(p &sync.PoolProcessor, idx int, worker_id int) voidptr {
 	// item := p.get_item<string>(idx)
 	item := p.get_string_item(idx)
 	println('worker_s worker_id: $worker_id | idx: $idx | item: ${item}')
-	time.sleep_ms(rand.next(3))
-	return &SResult{item + item}
-}
-
-struct IResult {
-	i int
+	time.sleep_ms(3)
+	return voidptr( &sync.SResult{ '${item} ${item}' } )
 }
 
 fn worker_i(p &sync.PoolProcessor, idx int, worker_id int) voidptr {
@@ -25,33 +16,47 @@ fn worker_i(p &sync.PoolProcessor, idx int, worker_id int) voidptr {
 	// item := p.get_item<int>(idx)
 	item := p.get_int_item(idx)
 	println('worker_i worker_id: $worker_id | idx: $idx | item: ${item}')
-	time.sleep_ms(rand.next(5))
-	return &IResult{item * 1000}
+	time.sleep_ms(5)
+	return voidptr( &sync.IResult{ item * 1000 } )
 }
 
 fn test_work_on_strings() {
-	rand.seed(0)
 	mut pool_s := sync.new_pool_processor({
 		callback: worker_s
 		maxjobs: 8
 	})
-	pool_s.work_on_items(['a','b','c','d','e','f','g','h','i','j'])
-	for x in pool_s.get_results<SResult>() {
+
+	// TODO: uncomment this when generics work again
+	//pool_s.work_on_items(['a','b','c','d','e','f','g','h','i','j'])
+	//for x in pool_s.get_results<SResult>() {
+	//	println( x.s )
+	//	assert x.s.len > 1
+	//}
+	   
+	pool_s.work_on_items_s(['a','b','c','d','e','f','g','h','i','j'])
+	for x in pool_s.get_results_s() {
 		println( x.s )
 		assert x.s.len > 1
 	}
 }
 
 fn test_work_on_ints() {
-	rand.seed(0)
 	// NB: since maxjobs is left empty here,
 	// the pool processor will use njobs = runtime.nr_jobs so that
 	// it will work optimally without overloading the system
 	mut pool_i := sync.new_pool_processor({
 		callback: worker_i
 	})
-	pool_i.work_on_items([1,2,3,4,5,6,7,8])
-	for x in pool_i.get_results<IResult>() {
+	   
+	// TODO: uncomment this when generics work again
+	//pool_i.work_on_items([1,2,3,4,5,6,7,8])
+	//for x in pool_i.get_results<IResult>() {
+	//	println( x.i )
+	//	assert x.i > 100
+	//}
+	   
+	pool_i.work_on_items_i([1,2,3,4,5,6,7,8])
+	for x in pool_i.get_results_i() {
 		println( x.i )
 		assert x.i > 100
 	}