NC | UploadPart | finish_upload | stat(part-{num}) should not check ctime due to concurrency part uploads of the same part.

[romayalon]

Explain the changes

1. Concurrent/retries uploadPart of the same part number caused InternalError with "cancelled due to ctime change" message. This error originated from stat(part-{num}), the last row of the stat code is check ctime change, which was changed during the retry of the same part.

Issues: Fixed #xxx / Gap #xxx

1. Fixed observed in noobaa log as "cancelled due to ctime change" actual upload didn't fail  #7833

Testing Instructions:

1. Couldn't reproduce it without adding sleep(10); in our native code, so adding manual testing instructions -

Pre Tests - 
1. update fs_napi.cpp FileStat function - add sleep(10); before the ctime check.
2. build the changes - node-gyp build

Tab 1 - 
1. Start NooBaa NSFS endpoint - 
sudo node src/cmd/nsfs.js --debug=5

Tab 2 -
2. Create Account - 
sudo node src/cmd/manage_nsfs.js account add --name account1 --uid=0 --gid=0 --new_buckets_path=/private/tmp/

3. Create s3 alias with account1 credentials, pointing to NooBaa endpoint -
alias s3api='AWS_ACCESS_KEY_ID=x AWS_SECRET_ACCESS_KEY=y aws --endpoint https://127.0.0.1:6443 --no-verify-ssl s3api'

4. Create a bucket using s3api- 
s3api create-bucket --bucket=buck1

5. Create MPU - 
s3api create-multipart-upload --bucket=buck1 --key=obj1

Tab 3 - 
6. Create s3 alias with account1 credentials, pointing to NooBaa endpoint -
alias s3api='AWS_ACCESS_KEY_ID=x AWS_SECRET_ACCESS_KEY=y aws --endpoint https://127.0.0.1:6443 --no-verify-ssl s3api'

7. create a file with some content - 
echo "blablbla" > bla

8. Upload the same part from Tab 2 and Tab 3 with a latency of less than 10 seconds - 
Tab 2 -
s3api upload-part --bucket buck1 --key obj1 --part-number 1 --upload-id {upload id specified at step 7} --body bla
Tab 3 (after 2 seconds) - 
s3api upload-part --bucket buck1 --key obj1 --part-number 1 --upload-id {upload id specified at step 7} --body bla

• Doc added/updated
• Tests added