tools: improve development experience for v -W -silent test-self vlib (especially on CIs); *always* show compilation errors for failures

Author: spytheman

cmd/tools/modules/testing/common.v

@@ -9,6 +9,7 @@ import sync
 import sync.pool
 import v.pref
 import v.util.vtest
+import v.util.vflags
 import runtime
 import rand
 import strings
@@ -410,7 +411,7 @@ fn worker_trunner(mut p pool.PoolProcessor, idx int, thread_id int) voidptr {
 	tls_bench.njobs = ts.benchmark.njobs
 	abs_path := os.real_path(p.get_item[string](idx))
 	mut relative_file := abs_path
-	mut cmd_options := [ts.vargs]
+	mut cmd_options := vflags.tokenize_to_args(ts.vargs) // make sure that `'-W -silent'` becomes `['-W', '-silent']`, while keeping quoted spaces intact
 	mut run_js := false
 
 	is_fmt := ts.vargs.contains('fmt')