scanner: uncomment working rune test (#25305)

vlib/v/scanner/scanner_test.v

@@ -151,16 +151,13 @@ fn test_ref_ref_array_ref_ref_foo() {
 }
 
 fn test_escape_rune() {
-	// these lines work if the v compiler is working
+	assert `\x61` == `a`
-	// will not work until v compiler on github is updated
+	assert `\u0061` == `a`
-	// assert `\x61` == `a`
+	assert `\U00000061` == `a`
-	// assert `\u0061` == `a`
-	// assert `\U00000061` == `a`
 
-	// will not work until PR is accepted
+	assert `\141` == `a`
-	// assert `\141` == `a`
+	assert `\xe2\x98\x85` == `★`
-	// assert `\xe2\x98\x85` == `★`
+	assert `\342\230\205` == `★`
-	// assert `\342\230\205` == `★`
 
 	// the following lines test the scanner module
 	// even before it is compiled into the v executable