vet: accumulate the collected errors manually (fixes CI)

cmd/tools/vvet.v

@@ -70,6 +70,6 @@ fn (mut vet_options VetOptions) vet_file(path string) {
 	table := table.new_table()
 	vet_options.vprintln("vetting file '$path'...")
 	file_ast, errors := parser.parse_vet_file(path, table, prefs)
-	vet_options.errors = errors
+	vet_options.errors << errors
 	vet.vet(file_ast, table, true)
 }

vlib/v/parser/parser.v

@@ -149,6 +149,7 @@ pub fn parse_vet_file(path string, table_ &table.Table, pref &pref.Preferences)
 		}
 	}
 	file := p.parse()
+	p.vet_errors << p.scanner.vet_errors
 	return file, p.vet_errors
 }
 

vlib/v/scanner/scanner.v

@@ -1394,10 +1394,6 @@ pub fn (s &Scanner) error(msg string) {
 
 fn (mut s Scanner) vet_error(msg string) {
 	eline := '$s.file_path:$s.line_nr: $msg'
-	if s.vet_errors.len == 0 {
-		eprintln(eline)
-		return
-	}
 	s.vet_errors << eline
 }