tests: Reduce compilation time and unneccessary recompiles by removing unused includes in tests

src/test/validation_block_tests.cpp

@@ -11,9 +11,12 @@
 #include <pow.h>
 #include <random.h>
 #include <test/setup_common.h>
+#include <util/time.h>
 #include <validation.h>
 #include <validationinterface.h>
 
+#include <thread>
+
 struct RegtestingSetup : public TestingSetup {
     RegtestingSetup() : TestingSetup(CBaseChainParams::REGTEST) {}
 };