Add null checks for CXPLAT_ALLOC_NONPAGED and CxPlatPoolAlloc calls

[Copilot]

This PR addresses missing null pointer checks for memory allocation functions CXPLAT_ALLOC_NONPAGED and CxPlatPoolAlloc in several locations throughout the codebase. Without these checks, allocation failures could lead to null pointer dereferences and undefined behavior.

Changes Made

src/perf/lib/Tcp.cpp

• Added null check for LocalTP allocation in InitializeTls() function
• Returns false with error message if allocation fails

src/core/unittest/RecvBufferTest.cpp

• Added null check for PreallocChunk allocation with proper QUIC_STATUS_OUT_OF_MEMORY return
• Added null check for AppOwnedBuffer allocation with proper error handling
• Added null checks for both CxPlatPoolAlloc calls with comprehensive resource cleanup to prevent memory leaks

src/platform/unittest/TlsTest.cpp

• Added null check for session ticket buffer allocation in OnSessionTicketReceived()
• Returns FALSE on allocation failure

Implementation Details

All changes follow existing error handling patterns found in the codebase:

• Use of QUIC_STATUS_OUT_OF_MEMORY for functions returning QUIC_STATUS
• Boolean false returns for functions with boolean return types
• Proper cleanup of previously allocated resources on subsequent allocation failures
• Consistent error messaging and logging

The implementation is minimal and surgical, adding only the necessary null checks without modifying existing functionality. All existing tests continue to pass, ensuring no regressions were introduced.

Fixes #5233.

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[ProjectsByJackHe]

Do you want to abandon this PR or does this need a review still? The NULL checks LGTM but your call @guhetier

[guhetier]

That one got buried under higher priority fixes, but it is ready. I rebased it if you can re-approve.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.01%. Comparing base (d597675) to head (f6cc9b4).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5326      +/-   ##
==========================================
- Coverage   85.36%   85.01%   -0.35%     
==========================================
  Files          60       60              
  Lines       18973    18973              
==========================================
- Hits        16196    16130      -66     
- Misses       2777     2843      +66     

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