Fix use-after-free in hashtableTwoPhasePopDelete

[zuiderkwast]

Use-after-free has been detect by address sanitizer, such as in this test run:

https://github.com/valkey-io/valkey/actions/runs/12981530413/job/36200075972?pr=1620#step:5:1339

hashtableShrinkIfNeeded may free one of the hash tables and invalidate the variables used by the fillBucketHole(ht, b, pos_in_bucket, table_index) just after, causing use-after-free. Fill bucket hole first and shrink afterwards is assumed to solve the issue. (Not reproduced locally.)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 71.01%. Comparing base (a18fcdb) to head (3daefd7).
Report is 2 commits behind head on unstable.

Additional details and impacted files

@@             Coverage Diff              @@
##           unstable    #1626      +/-   ##
============================================
+ Coverage     70.84%   71.01%   +0.17%     
============================================
  Files           121      121              
  Lines         65169    65169              
============================================
+ Hits          46172    46283     +111     
+ Misses        18997    18886     -111     

Files with missing lines	Coverage Δ
src/hashtable.c	78.08% <100.00%> (-0.43%)	⬇️

... and 8 files with indirect coverage changes