Use initial capacity for map if possible

[snuyanzin]

No description provided.

[what-the-diff]

PR Summary

This pull request modifies several files in our codebase to make our program more efficient and code cleaner.

• Refactoring of Xml.java and BaseFaker.java
  These files have been updated to better create and initialize maps, which can significantly increase the performance in our code. Drop of java.util.HashMap import statement reduces dependencies and makes our code less complex.

• Improvements in FakeValues.java
  We've addressed the way our program creates nested maps, making it more efficient. There's also a change in the way we're utilizing the HashMap constructor which should enhance the code performance as well.

• Brightening up FakeValuesService.java
  Several if statements have been converted to the new switch expression syntax. It's a fresh Java feature that makes our code more readable and streamlined.

• Cleaning up JsonTransformer.java and XmlTransformer.java
  Removed unnecessary import statements from these files and adjusted the createEscapeMap() method for cleaner code and better performance. Plus, the code inside the pretty() method definition in XmlTransformer.java got an indentation fix for better readability.

• Maintaining the BaseFakerTest.java test file
  Cleaned up some import statements that were no longer used. Also, the fakeValuesHaveReproducibleValues() method name has been changed to fakeValuesHaveReproducibleValuesTest(). The new name better suits the function of the method, making the code easier to read and understand for everyone.

[codecov-commenter]

Codecov Report

Attention: 5 lines in your changes are missing coverage. Please review.

Comparison is base (e90cc2f) 92.18% compared to head (517d10b) 92.10%.
Report is 1 commits behind head on main.

Files	Patch %	Lines
...n/java/net/datafaker/providers/base/BaseFaker.java	62.50%	3 Missing ⚠️
.../java/net/datafaker/service/FakeValuesService.java	75.00%	1 Missing and 1 partial ⚠️

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Additional details and impacted files

@@             Coverage Diff              @@
##               main    #1057      +/-   ##
============================================
- Coverage     92.18%   92.10%   -0.09%     
+ Complexity     2762     2760       -2     
============================================
  Files           291      291              
  Lines          5543     5536       -7     
  Branches        600      599       -1     
============================================
- Hits           5110     5099      -11     
- Misses          276      280       +4     
  Partials        157      157              

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