Fail early & more clearly on shaded-broken classfiles #31877

Job	Run time
test	41m 20s
test_non_bootstrapped	0s
test_scala2_library_tasty	0s
test_windows_fast	46m 30s
MiMa	11m 13s
community_build_a	57m 15s
test_windows_full	0s
community_build_b	1h 22m 37s
community_build_c	1h 1m 29s
test_java8	0s
test_sbt	17m 36s
build-msi-package	0s
build-sdk-package / build	7m 42s
build-chocolatey-package / build	22s
test-chocolatey-package	0s
publish_nightly	0s
publish_release	0s
nightly_documentation	0s
open_issue_on_failure	0s
	5h 26m 4s

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