strings: fix using array_push_many inside write_string + gc, not using array_push_many_noscan (part 1)

Author: spytheman

vlib/builtin/array_d_gcboehm_opt.v

@@ -255,7 +255,7 @@ fn (mut a array) push_noscan(val voidptr) {
 // push_many implements the functionality for pushing another array.
 // `val` is array.data and user facing usage is `a << [1,2,3]`
 @[unsafe]
-fn (mut a3 array) push_many_noscan(val voidptr, size int) {
+pub fn (mut a3 array) push_many_noscan(val voidptr, size int) {
 	if size <= 0 || val == unsafe { nil } {
 		return
 	}

vlib/strings/builder.c.v

@@ -134,7 +134,11 @@ pub fn (mut b Builder) write_string(s string) {
 	if s.len == 0 {
 		return
 	}
-	unsafe { b.push_many(s.str, s.len) }
+	$if gcboehm ? {
+		unsafe { b.push_many_noscan(s.str, s.len) }
+	} $else {
+		unsafe { b.push_many(s.str, s.len) }
+	}
 	// for c in s {
 	// b.buf << c
 	// }