Record length columns cannot be used when `strict_integral_precision=true`

[yruslan]

Describe the bug

This is because when strict_integral_precision = true integral fields become decimal.

Nothing prevents from using decimals for record length, especially when scale=0.

Originally described here: #750

Code snippet that caused the issue

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Expected behavior

Record length fields should work with decimal fields.

Context

• Cobrix version: 2.8.3

Copybook

         01  RECORD.
           05  REC-LEN    PIC S9(4).