Cleaned up and refactor Volt parser

[sergeyklay]

Hello!

• Type: code quality
• Link to issue: -

In raising this pull request, I confirm the following:

• I have read and understood the Contributing Guidelines
• I have checked that another pull request for this purpose does not exist
• I wrote some tests for this PR

Small description of change:

• Cleaned up and refactor Volt parser
• Fixed C compiler warnings

Thanks

[codecov]

Codecov Report

Merging #13755 into 4.0.x will decrease coverage by <.01%.
The diff coverage is 76.66%.

@@            Coverage Diff             @@
##            4.0.x   #13755      +/-   ##
==========================================
- Coverage   65.66%   65.66%   -0.01%     
==========================================
  Files         396      396              
  Lines       88240    88244       +4     
==========================================
+ Hits        57945    57947       +2     
- Misses      30295    30297       +2

Impacted Files	Coverage Δ
ext/phalcon/mvc/view/engine/volt/scanner.c	76.47% <ø> (ø)	⬆️
ext/phalcon/mvc/view/engine/volt/parser.c	77.48% <68.42%> (-0.11%)	⬇️
ext/phalcon/mvc/view/engine/volt/parser.php7.inc.h	84.49% <90.9%> (ø)	⬆️

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