Various fixes caught by CLANG

[kuqin12]

Preface

Please ensure you have read the contribution docs prior
to submitting the pull request. In particular,
pull request guidelines.

Description

This change will cover a few more CLANG fixes, including uninitialized variables and unintentionally pulled in compiler intrinsics.

For each item, place an "x" in between [ and ] if true. Example: [x].
(you can also check items in the GitHub UI)

• Impacts functionality?
  • Functionality - Does the change ultimately impact how firmware functions?
  • Examples: Add a new library, publish a new PPI, update an algorithm, ...
• Impacts security?
  • Security - Does the change have a direct security impact on an application,
    flow, or firmware?
  • Examples: Crypto algorithm change, buffer overflow fix, parameter
    validation improvement, ...
• Breaking change?
  • Breaking change - Will anyone consuming this change experience a break
    in build or boot behavior?
  • Examples: Add a new library class, move a module to a different repo, call
    a function in a new library class in a pre-existing module, ...
• Includes tests?
  • Tests - Does the change include any explicit test code?
  • Examples: Unit tests, integration tests, robot tests, ...
• Includes documentation?
  • Documentation - Does the change contain explicit documentation additions
    outside direct code modifications (and comments)?
  • Examples: Update readme file, add feature readme file, link to documentation
    on an a separate Web page, ...

How This Was Tested

This was tested on QEMU Q35.

Integration Instructions

N/A

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.

Project coverage is 0.31%. Comparing base (548aad1) to head (0307d7b).

Files	Patch %	Lines
MmSupervisorPkg/Core/Request/UnblockMemory.c	0.00%	3 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##            main    #303      +/-   ##
========================================
- Coverage   0.47%   0.31%   -0.17%     
========================================
  Files        144     144              
  Lines      22079   22061      -18     
  Branches      60      60              
========================================
- Hits         105      69      -36     
+ Misses     21969   21965       -4     
- Partials       5      27      +22     

Flag	Coverage Δ
MmSupervisorPkg	0.31% <0.00%> (-0.17%)	⬇️

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