fix: size float scratch buffer from its documented bound

Author: JairusSW

std/assembly/util/dtoa.ts

@@ -1,5 +1,5 @@
 import { CharCode, POWERS10 } from "./string";
-import { DIGITS, MAX_DOUBLE_LENGTH } from "./number";
+import { DIGITS } from "./number";
 
 // Fixed-point log significands shared by the dec-exp / binary-exp estimates below.
 @lazy @inline const LOG10_2_SIGNIFICAND = 0x4D105; // ~(log10(2) * 2**20)

std/assembly/util/number.ts

@@ -410,7 +410,7 @@ export function itoa64(value: i64, radix: i32): String {
 
 
 // @ts-ignore: decorator
-@lazy @inline const dtoa_buf = memory.data(128);
+@lazy @inline const dtoa_buf = memory.data(MAX_DOUBLE_LENGTH << 1);
 
 export function dtoa<T extends number>(value: T): String {
   if (value == 0) return "0.0";