Removed pointless property and variables from Volt compiler

[SidRoberts]

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
• [-] I updated the CHANGELOG

Previously a variable was "cached" as a property.

[codecov]

Codecov Report

Merging #13925 into 4.0.x will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##            4.0.x   #13925      +/-   ##
==========================================
- Coverage   67.63%   67.63%   -0.01%     
==========================================
  Files         469      469              
  Lines       94345    94340       -5     
==========================================
- Hits        63814    63809       -5     
  Misses      30531    30531

Impacted Files	Coverage Δ
ext/phalcon/mvc/view/engine/volt/compiler.zep.c	66.34% <0%> (-0.06%)	⬇️

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[niden]

Can you add an entry in the CHANGELOG please @SidRoberts

[SidRoberts]

@niden Changelog updated and rebased to avoid conflicts.

[niden]

@SidRoberts Thank you!