GTiff multithreaded reading/writing: fix a deadlock situation

[rouault]

Fix a deadlock encountered with
gdalwarp test1.tif test2.tif -co COMPRESS=LZW -co TILED=YES -co BLOCKXSIZE=256 -co BLOCKYSIZE=256 -co BIGTIFF=YES -multi -co NUM_THREADS=ALL_CPUS out.tif -overwrite
on the test datasets provided in #8470 (comment)

[rouault]

manually cherry picked to 3.7 per b5858ed

[rouault]

The backport to release/3.7 failed:

The process '/usr/bin/git' failed with exit code 1

stderr

error: could not apply d083af1ec9... GTiff multithreaded reading/writing: fix a deadlock situation
hint: After resolving the conflicts, mark them with
hint: "git add/rm <pathspec>", then run
hint: "git cherry-pick --continue".
hint: You can instead skip this commit with "git cherry-pick --skip".
hint: To abort and get back to the state before "git cherry-pick",
hint: run "git cherry-pick --abort".

stdout

CONFLICT (modify/delete): frmts/gtiff/gtiffdataset_read.cpp deleted in HEAD and modified in d083af1ec9 (GTiff multithreaded reading/writing: fix a deadlock situation).  Version d083af1ec9 (GTiff multithreaded reading/writing: fix a deadlock situation) of frmts/gtiff/gtiffdataset_read.cpp left in tree.

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-release/3.7 release/3.7
# Navigate to the new working tree
cd .worktrees/backport-release/3.7
# Create a new branch
git switch --create backport-8561-to-release/3.7
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick d083af1ec9c38e79bfb0532885570de6e5b8a410
# Push it to GitHub
git push --set-upstream origin backport-8561-to-release/3.7
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-release/3.7

Then, create a pull request where the base branch is release/3.7 and the compare/head branch is backport-8561-to-release/3.7.