Make q10-11 compression floating-point-free

Hi there,

I found that brotli would emit different compressed files if I compiled with different compilers.

- Version : git head at the time of report (commit 62662f87cdd96deda90ac817de94e3c4af75226a)
- Compiler : clang13 and gcc11
- Reproduce: 1) compile with clang13 and gcc11 separately. 2) run `brotli -fq 11 diff_0 -o output` with two `brotli` compiled by different compilers. 3) You'll see they emit different compressed output files.
- Test case: [diff_0.tar.gz](https://github.com/google/brotli/files/7390780/diff_0.tar.gz) (decompress it first).

Thanks,
Shaohua