buffer.toString() fails when buffer.length >= 32 and null-terminated on big-endian

### Version v24.18.0, v26.5.0 ### Platform ```text Linux zelenka 6.12.96+deb13-s390x #1 SMP Debian 6.12.96-1 (2026-07-20) s390x GNU/Linux ``` ### Subsystem StringBytes ### What steps will reproduce the bug? Run these commands ```sh node -p 'const b=Buffer.alloc(32); b.write("\u3000",0,"utf8");b.toString().charCodeAt(0);' node -p 'Buffer.from("\u3000").toString().charCodeAt(0);' ``` ### How often does it reproduce? Is there a required condition? Always reproduced on big-endian. ### What is the expected behavior? Why is that the expected behavior? both commands should return 12288 ### What do you see instead? On big-endian architecture (e.g. s390x) the first call returns 0 and the last 12288. ### Additional information Tested with the executables provided by nodejs.org. v22.23.1 is not affected. Also, this gives the correct result on big-endian: ``` node -p 'const b=Buffer.alloc(31); b.write("\u3000",0,"utf8");b.toString().charCodeAt(0);' ``` So the suspected commits are the ones adding the special cases for `buflen >= 32` here: https://github.com/nodejs/node/blob/68130800586634f17812f3b0837d869a36725e98/src/string_bytes.cc#L751 and here https://github.com/nodejs/node/blob/68130800586634f17812f3b0837d869a36725e98/src/string_bytes.cc#L625