Fix compilation warnings from VS2019

[jslee02]

Build log of the warnings

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Before creating a pull request

• Document new methods and classes
• Format new code files using clang-format

Before merging a pull request

• Set version target by selecting a milestone on the right side
• Summarize this change in CHANGELOG.md
• Add unit test(s) for this change

[codecov]

Codecov Report

Merging #1402 into master will increase coverage by 0.01%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master    #1402      +/-   ##
==========================================
+ Coverage   57.27%   57.28%   +0.01%     
==========================================
  Files         366      366              
  Lines       27432    27432              
==========================================
+ Hits        15711    15714       +3     
+ Misses      11721    11718       -3

Impacted Files	Coverage Δ
dart/utils/XmlHelpers.cpp	60.84% <0%> (ø)	⬆️
dart/dynamics/SharedLibraryIkFast.cpp	49.41% <0%> (ø)	⬆️
dart/dynamics/Skeleton.cpp	66.22% <0%> (+0.16%)	⬆️