bytearray slice assignment for bytes-like object is much slower than that for bytearray

Bug report

bytearray slice assignment for bytes-like object is much slower than that for bytearray

On my machine:
python -m timeit -s "a=bytearray(4096);b=b'x'*1024;" "a[:1024]=b"
1000000 loops, best of 5: 296 nsec per loop
python -m timeit -s "a=bytearray(4096);b=memoryview(b'x'*1024);" "a[:1024]=b"
1000000 loops, best of 5: 293 nsec per loop
python -m timeit -s "a=bytearray(4096);b=bytearray(b'x'*1024);" "a[:1024]=b"
5000000 loops, best of 5: 80.4 nsec per loop

On official Python playground(https://www.python.org/shell/):
import timeit
timeit.main(["-s", "a=bytearray(4096);b=b'x'*1024;", "a[:1024]=b"])
1000000 loops, best of 5: 272 nsec per loop
timeit.main(["-s", "a=bytearray(4096);b=memoryview(b'x'*1024);", "a[:1024]=b"])
1000000 loops, best of 5: 268 nsec per loop
timeit.main(["-s", "a=bytearray(4096);b=bytearray(b'x'*1024);", "a[:1024]=b"])
5000000 loops, best of 5: 78.8 nsec per loop

Your environment

• CPython versions tested on: 3.11.1
• Operating system and architecture: Windows 10 22H2 x86-64

Linked PRs

• gh-101445

首先，在指定的 CPython 版本上重现 issue 中给出的三个 python -m timeit 基准测试，并比较 bytearray、bytes 和 memoryview 的情况。查看已链接的 PR gh-101445，了解与此 issue 已关联的工作；完成的实现应解决报告的性能差距，同时不回归切片赋值行为。