Fix flaky parallel dirOps e2e tests

[Tulsishah]

Description

Potential Problems:

1. Data Race: The update to statInfo and lookUpErr in the goroutine may not be visible to the main thread immediately.
   This can lead to a situation where lookUpErr == nil, but statInfo still appears nil in the main thread and cause panic.
2. Improper Synchronization: Even though we're using sync.WaitGroup to wait for goroutines to finish, there is no explicit guarantee that statInfo and lookUpErr are synchronized across goroutines and the main thread.

Applied Fixes:

1. Use pointers to pass results (statInfo, lookUpErr, etc.) directly to avoid shared variable conflicts.
2. Avoid Shared Variables: Each goroutine updates its respective variables, ensuring no concurrent writes to shared memory.
3. Thread-Safe Updates: By passing pointers, the main thread accesses fully updated variables after wg.Wait().

Link to the issue in case of a bug fix.

1. b/387209276
2. b/383948909
3. b/386583075

Testing details

1. Manual - NA
2. Unit tests - NA
3. Integration tests - Automated

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 76.10%. Comparing base (84f8195) to head (3b9d79f).
Report is 6 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2852      +/-   ##
==========================================
+ Coverage   76.08%   76.10%   +0.01%     
==========================================
  Files         118      118              
  Lines       16557    16557              
==========================================
+ Hits        12598    12601       +3     
+ Misses       3427     3425       -2     
+ Partials      532      531       -1     

Flag	Coverage Δ
unittests	76.10% <ø> (+0.01%)	⬆️

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