fix flag disableDecNumCheck

Bug: disableDecNumCheck always disabled also declaration order check.
In other words behavior was identical:

  - with only disableDecNumCheck,
  - with both disableDecNumCheck and disableDecOrderCheck.

Fix: Always gather tokenCounts, because they are needed for both the
declaration-order check and the declaration-number check.

This doesn't impact the golangci-lint default behavior, for two reasons:

  - golangci-lint does not enable "decorder" by default,
  - golangci-lint sets disableDecNumCheck and disableDecOrderCheck
    to true by default.