Fixed invalid ZEPHIR_METHOD_GLOBALS_PTR call

[sergeyklay]

Hello!

• Type: bug fix
• Link to issue: [0.12.5] broken build #1940

In raising this pull request, I confirm the following:

• I have checked that another pull request for this purpose does not exist
• I wrote some tests for this PR
• I updated the CHANGELOG

Fixed invalid zephir_json_encode and zephir_json_decode call or those users who doesn't use
bundled ext/json/php_json.h

Thanks

[codecov]

Codecov Report

Merging #1942 into development will decrease coverage by <.01%.
The diff coverage is n/a.

@@                Coverage Diff                @@
##             development    #1942      +/-   ##
=================================================
- Coverage          33.99%   33.99%   -0.01%     
  Complexity          8252     8252              
=================================================
  Files                561      561              
  Lines              44931    44930       -1     
=================================================
- Hits               15275    15274       -1     
  Misses             29656    29656