v1.6.3.73 style: frun_GR6J subroutine is compliant with Fortran 95 standard

Reviewed-by: @antoine.pelletier
Refs #68
4 jobs for 68-non-compliance-with-fortran-95-standard in 12 minutes and 29 seconds (queued for 1 minute and 30 seconds)
Status Job ID Name Coverage
  Build
passed #131840
build_patched

00:00:25

 
  Regression
passed #131841
regression_patched

00:00:58

 
  Tests
passed #131843
check_as_cran_patched

00:02:17

passed #131842
check_not_cran_patched

00:08:47