libfdtrack: When dump fdsan fd owner, happen NE

When dump fdsan fd owner, happen NE. This because the format specifier
flag '#' is not supported by Bionic out_vformat<BufferOutputStream>.

Bug: 153611483
Test: jmgao@ verified manually
Change-Id: I7191c3b2b621ddcc0397874f8a69391e58232ac8
diff --git a/libfdtrack/fdtrack.cpp b/libfdtrack/fdtrack.cpp
index b20e65e..8d9d61d 100644
--- a/libfdtrack/fdtrack.cpp
+++ b/libfdtrack/fdtrack.cpp
@@ -166,7 +166,7 @@
          void*) {
         uint64_t fdsan_owner = android_fdsan_get_owner_tag(fd);
         if (fdsan_owner != 0) {
-          async_safe_format_log(ANDROID_LOG_INFO, "fdtrack", "fd %d: (owner = %#" PRIx64 ")", fd,
+          async_safe_format_log(ANDROID_LOG_INFO, "fdtrack", "fd %d: (owner = 0x%" PRIx64 ")", fd,
                                 fdsan_owner);
         } else {
           async_safe_format_log(ANDROID_LOG_INFO, "fdtrack", "fd %d: (unowned)", fd);