tools.vet: update diff comparison in vet_test.v (#21457)

Author: ttytm

cmd/tools/vvet/vet_test.v

@@ -1,16 +1,8 @@
 import os
-import rand
 import term
 import v.util.vtest
 import v.util.diff
 
-const diff_cmd = find_diff_cmd()
-
-fn find_diff_cmd() string {
-	res := diff.find_working_diff_command() or { '' }
-	return res
-}
-
 fn test_vet() {
 	vexe := os.getenv('VEXE')
 	vroot := os.dir(vexe)
@@ -44,14 +36,16 @@ fn check_path(vexe string, dir string, tests []string) int {
 		if expected != found {
 			println(term.red('FAIL'))
 			println('============')
-			println('expected:')
-			println(expected)
-			println('============')
-			println('found:')
-			println(found)
-			println('============\n')
-			println('diff:')
-			println(diff.color_compare_strings(diff_cmd, rand.ulid(), expected, found))
+			if diff_ := diff.compare_text(expected, found) {
+				println('diff:')
+				println(diff_)
+			} else {
+				println('expected:')
+				println(expected)
+				println('============')
+				println('found:')
+				println(found)
+			}
 			println('============\n')
 			nb_fail++
 		} else {