Style: clang-format: Disable KeepEmptyLinesAtTheStartOfBlocks

Which means that reduz' beloved style which we all became used to
will now be changed automatically to remove the first empty line.

This makes us lean closer to 1TBS (the one true brace style) instead
of hybridating it with some Allman-inspired spacing.

There's still the case of braces around single-statement blocks that
needs to be addressed (but clang-format can't help with that, but
clang-tidy may if we agree about it).

Part of #33027.

main/tests/test_oa_hash_map.cpp

@@ -36,7 +36,6 @@
 namespace TestOAHashMap {
 
 MainLoop *test() {
-
 	OS::get_singleton()->print("\n\n\nHello from test\n");
 
 	// test element tracking.
@@ -122,7 +121,6 @@ MainLoop *test() {
 
 	// regression test / test for issue related to #31402
 	{
-
 		OS::get_singleton()->print("test for issue #31402 started...\n");
 
 		const int num_test_values = 12;