clang-tidy: Apply modernize-deprecated-headers

This can be reproduced according to the developer notes with something
like

( cd ./src/ && ../contrib/devtools/run-clang-tidy.py -p ../bld-cmake -fix -j $(nproc) )

Also, the header related changes were done manually.

src/wallet/test/wallet_tests.cpp

@@ -6,7 +6,7 @@
 
 #include <future>
 #include <memory>
-#include <stdint.h>
+#include <cstdint>
 #include <vector>
 
 #include <addresstype.h>