Be sure we to read all bytes requested, in GetRandomBytes.

runtime/bin/crypto_macos.cc

Index: runtime/bin/crypto_macos.cc
diff --git a/runtime/bin/crypto_macos.cc b/runtime/bin/crypto_macos.cc
index 36020d4a7f307e2271176e681c37915f41ade1fb..d808d416b608a571c807fa9fcfc6f97ae6396d37 100644
--- a/runtime/bin/crypto_macos.cc
+++ b/runtime/bin/crypto_macos.cc
@@ -20,8 +20,8 @@ namespace bin {
 bool Crypto::GetRandomBytes(intptr_t count, uint8_t* buffer) {
   intptr_t fd = TEMP_FAILURE_RETRY(open("/dev/urandom", O_RDONLY));
   if (fd < 0) return false;
-  intptr_t bytes_read = read(fd, buffer, count);
-  close(fd);
+  intptr_t bytes_read = FDUtils::ReadFromBlocking(fd, buffer, count);
+  VOID_TEMP_FAILURE_RETRY(close(fd));
   return bytes_read == count;
 }