Fix warning message for matching on redundant nulls #33053

Job	Run time
MiMa	10m 27s
test	54m 46s
test_non_bootstrapped	0s
test_scala2_library_tasty	0s
test_windows_fast	32m 14s
test_windows_full	0s
build-msi-package	0s
community_build_a	1h 0m 6s
community_build_b	1h 17m 26s
community_build_c	1h 7m 40s
test_java8	0s
test_sbt	17m 20s
build-sdk-package / build	7m 56s
test-msi-package	0s
build-chocolatey-package / build	30s
test-chocolatey-package	0s
publish_nightly	0s
publish_release	0s
nightly_documentation	0s
open_issue_on_failure	0s
	5h 28m 25s

Provide feedback