test/*: add missing includes for fprintf()

test/FakeDecoderAPI.cxx

@@ -25,6 +25,7 @@
 #include "Compiler.h"
 
 #include <unistd.h>
+#include <stdio.h>
 
 void
 decoder_initialized(Decoder &decoder,

test/run_convert.cxx

@@ -35,6 +35,7 @@
 #include <assert.h>
 #include <stddef.h>
 #include <stdlib.h>
+#include <stdio.h>
 #include <unistd.h>
 
 int main(int argc, char **argv)

test/run_storage.cxx

@@ -28,6 +28,7 @@
 
 #include <unistd.h>
 #include <stdlib.h>
+#include <stdio.h>
 #include <string.h>
 #include <time.h>
 

test/visit_archive.cxx

@@ -31,6 +31,7 @@
 
 #include <unistd.h>
 #include <stdlib.h>
+#include <stdio.h>
 
 class MyArchiveVisitor final : public ArchiveVisitor {
  public: