file_test: Fix file test

Trimming of the line feed is no longer necessary after
https://github.com/file/file/commit/d993c6b0db20711b2c4cb9d2bee8c7f2e59b0a43

Currently the tests:

  - bcachefs2
  - gpkg-1-zst
  - multiple

are failing, but a fix will be committed upstream.

This also reverts c5e957ad4 "file: fix test case for gpkg by removing the extra \n."

MFC after:	3 days

contrib/file/tests/gpkg-1-zst.result

@@ -1 +1 @@
-Gentoo GLEP 78 (GPKG) binary package for "inkscape-1.2.1-r2-1" using zstd compression
+Gentoo GLEP 78 (GPKG) binary package for "inkscape-1.2.1-r2-1" using zstd compression

usr.bin/file/tests/file_test.sh

@@ -40,8 +40,7 @@ contrib_file_tests_body() {
 		# The result files were created in UTC.
 		TZ=Z atf_check -o save:actual_output file ${file_args} \
 		    --brief "$testfile"
-		atf_check -o save:trimmed_output tr -d '\012' < actual_output
-		atf_check cmp trimmed_output "$result_file"
+		atf_check cmp actual_output "$result_file"
 	done
 }