builtin: use malloc_noscan more (for map metas and in []byte.hex())

vlib/builtin/array.v

@@ -791,7 +791,7 @@ pub fn (a []string) str() string {
 // hex returns a string with the hexadecimal representation
 // of the byte elements of the array.
 pub fn (b []byte) hex() string {
-	mut hex := unsafe { malloc(b.len * 2 + 1) }
+	mut hex := unsafe { malloc_noscan(b.len * 2 + 1) }
 	mut dst_i := 0
 	for i in b {
 		n0 := i >> 4

vlib/builtin/builtin.c.v

@@ -324,7 +324,7 @@ pub fn malloc_noscan(n int) &byte {
 	}
 	$if trace_malloc ? {
 		total_m += n
-		C.fprintf(C.stderr, c'_v_malloc %6d total %10d\n', n, total_m)
+		C.fprintf(C.stderr, c'malloc_noscan %6d total %10d\n', n, total_m)
 		// print_backtrace()
 	}
 	mut res := &byte(0)

vlib/builtin/map.v

@@ -662,7 +662,7 @@ pub fn (m &map) clone() map {
 		cached_hashbits: m.cached_hashbits
 		shift: m.shift
 		key_values: unsafe { m.key_values.clone() }
-		metas: unsafe { &u32(malloc(metasize)) }
+		metas: unsafe { &u32(malloc_noscan(metasize)) }
 		extra_metas: m.extra_metas
 		len: m.len
 		has_string_keys: m.has_string_keys

vlib/builtin/rune.v

@@ -18,7 +18,7 @@ pub fn (c rune) str() string {
 		println('len=$len')
 		mut str := string{
 			len: len
-			str: malloc(len + 1)
+			str: malloc_noscan(len + 1)
 		}
 		for i in 0..len {
 			str.str[i] = byte(int(c)>>8 * (3 - i) & 0xff)