Fix valgrind errors.

c++/src/kj/async-io-unix.c++

@@ -782,8 +782,10 @@ public:
   }
 
 private:
-  SocketAddress(): addrlen(0) {
-    memset(&addr, 0, sizeof(addr));
+  SocketAddress() {
+    // We need to memset the whole object 0 otherwise Valgrind gets unhappy when we write it to a
+    // pipe, due to the padding bytes being uninitialized.
+    memset(this, 0, sizeof(*this));
   }
 
   socklen_t addrlen;

c++/src/kj/table.c++

@@ -809,7 +809,7 @@ const InsertionOrderIndex::Link InsertionOrderIndex::EMPTY_LINK = { 0, 0 };
 
 InsertionOrderIndex::InsertionOrderIndex(): capacity(0), links(const_cast<Link*>(&EMPTY_LINK)) {}
 InsertionOrderIndex::~InsertionOrderIndex() noexcept(false) {
-  if (links != &EMPTY_LINK) delete links;
+  if (links != &EMPTY_LINK) delete[] links;
 }
 
 void InsertionOrderIndex::reserve(size_t size) {

super-test.sh

@@ -516,7 +516,7 @@ if [ "x`uname`" != xDarwin ] && which valgrind > /dev/null; then
   # Running the fuzz tests under Valgrind is a great thing to do -- but it takes
   # some 40 minutes. So, it needs to be done as a separate step of the release
   # process, perhaps along with the AFL tests.
-  CAPNP_SKIP_FUZZ_TEST=1 doit valgrind --leak-check=full --track-fds=yes --error-exitcode=1 ./capnp-test
+  CAPNP_SKIP_FUZZ_TEST=1 doit valgrind --leak-check=full --track-fds=yes --error-exitcode=1 --child-silent-after-fork=yes --sim-hints=lax-ioctls ./capnp-test
 fi
 
 doit make maintainer-clean