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/test/util/cluster_linearize.h

@@ -12,7 +12,7 @@
 #include <util/bitset.h>
 #include <util/feefrac.h>
 
-#include <stdint.h>
+#include <cstdint>
 #include <numeric>
 #include <vector>
 #include <utility>

src/test/util/coins.cpp

@@ -10,7 +10,7 @@
 #include <test/util/random.h>
 #include <uint256.h>
 
-#include <stdint.h>
+#include <cstdint>
 #include <utility>
 
 COutPoint AddTestCoin(FastRandomContext& rng, CCoinsViewCache& coins_view)