Fix promoted default values

[oprypkhantc]

Hey

Currently constructor promoted properties' default values are ignored, because ReflectionClass::getDefaultProperties() does not return default values from promoted props.

This fixes it, so the behaviour matches regular properties.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.28%. Comparing base (53f9d49) to head (e8f2c4a).
Report is 76 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #672      +/-   ##
============================================
- Coverage     95.72%   95.28%   -0.45%     
- Complexity     1773     1828      +55     
============================================
  Files           154      171      +17     
  Lines          4586     4854     +268     
============================================
+ Hits           4390     4625     +235     
- Misses          196      229      +33     

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