(Closes #1558) support out-of-order parameter statements

[arporter]

This PR simply moves the existing functionality for processing PARAMETER statements into a separate routine which can then be called once all the variable declarations have been processed.

[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (f54db94) 99.85% compared to head (35ad0b9) 99.85%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #2309   +/-   ##
=======================================
  Coverage   99.85%   99.85%           
=======================================
  Files         339      339           
  Lines       46054    46069   +15     
=======================================
+ Hits        45985    46000   +15     
  Misses         69       69           

Files Changed	Coverage Δ
src/psyclone/psyir/frontend/fparser2.py	100.00% <100.00%> (ø)
...ts/psyir/frontend/fparser2_parameter_stmts_test.py	100.00% <100.00%> (ø)

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[arporter]

CI is happy. Have launched the integration tests...

[arporter]

Integration tests are green too. Ready for review from either @sergisiso or @rupertford I think.

[sergisiso]

@arporter This is a enhancement of fparserreader to support out-of-order parameters statements. The relevant code is unmodified but moved into a subroutine and triggered later. I agree with the movement. All tests, formatters, codecov and abscense of TODO and integration tests have passed. This is ready to merge, but I will wait for #2301 as it was marked ready first.