ls: test_ls_allocation_size fails on filesystem f2fs (android)

[cre4ture]

Extracted new issue from topic in PR #5821:

When running the uutils test-suite on my real android device (also confirmed by @samueltardieu in #5821),
then this test (apart from others) fails:

---- test_ls::test_ls_allocation_size stdout ----
mkdir: /data/data/com.termux/files/usr/tmp/.tmpzzgyw7/some-dir1
touch: /data/data/com.termux/files/usr/tmp/.tmpzzgyw7/some-dir1/empty-file
run: /data/data/com.termux/files/home/rust/coreutils/target/debug/coreutils truncate -s 4M some-dir1/file-with-holes
run: /data/data/com.termux/files/home/rust/coreutils/target/debug/coreutils dd if=/dev/zero of=some-dir1/zero-file bs=1024 count=4096
run: /data/data/com.termux/files/home/rust/coreutils/target/debug/coreutils dd if=/dev/zero of=irregular-file bs=1 count=777
run: /data/data/com.termux/files/home/rust/coreutils/target/debug/coreutils ls -l --block-size=512 irregular-file
run: /data/data/com.termux/files/home/rust/coreutils/target/debug/coreutils ls -s1 some-dir1
thread 'test_ls::test_ls_allocation_size' panicked at tests/by-util/test_ls.rs:124:14:
assertion failed: `(left == right)`

Diff < left / right > :
<total 4100
>total 4096
    0 empty-file
    0 file-with-holes
<4100 zero-file
>4096 zero-file
 


note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace


failures:
    test_ls::test_ls_allocation_size

It seems that the allocated size on "f2fs" is always slightly larger than on traditional filesystems.
After reading a bit about this filesystem type, I concluded that this probably makes sense due to the nature of this filesystem.
Thus, I adapted the test according to the underlying filesystem.