check_format.pl: fix detection of 'if' with single stmt in braces wit… #2142

Job	Run time
basic_clang	5m 53s
check_docs	1m 1s
basic_gcc	5m 53s
check_update	1m 17s
check-ansi	2m 30s
minimal	2m 34s
no-deprecated	5m 31s
non-caching	15m 27s
no-shared-macos (macos-13)	6m 11s
no-shared-ubuntu	4m 43s
no-shared-macos (macos-14)	3m 33s
address_ub_sanitizer	11m 4s
enable_non-default_options	4m 43s
external-test-cf-quiche	3m 31s
external-test-pyca (1.51.0, 3.9)	7m 13s
external-tests	11m 31s
full_featured	6m 8s
fuzz_tests	3m 10s
legacy	4m 40s
memory_sanitizer	21m 46s
no-legacy	5m 43s
out-of-readonly-source-and-install-macos (macos-13)	10m 25s
out-of-readonly-source-and-install-ubuntu	7m 36s
out-of-readonly-source-and-install-macos (macos-14)	6m 24s
self-hosted	0s
threads_sanitizer	5m 34s
	2h 44m 1s

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