huf log speed optimization: unidirectional scan of logs + break when regressing

tests/cli-tests/compression/window-resize.sh

@@ -0,0 +1,9 @@
+#!/bin/sh
+datagen -g1G > file
+zstd --long=31 -1 --single-thread --no-content-size -f file
+zstd -l -v file.zst
+
+# We want to ignore stderr (its outputting "*** zstd command line interface
+# 64-bits v1.5.3, by Yann Collet ***")
+
+rm file file.zst

tests/cli-tests/compression/window-resize.sh.stdout.glob

@@ -0,0 +1,3 @@
+...
+Window Size: 1.000 GiB (1073741824 B)
+...