hg: tsan/dev: Change a wrong type to fix build

[aeubanks at google.com]

Changeset: 1c8f3ed98dd6
Author:    aeubanks
Date:      2019-03-27 16:19 -0700
URL:       http://hg.openjdk.java.net/tsan/dev/rev/1c8f3ed98dd6

Change a wrong type to fix build

JVM doesn't recognize "int64", use "julong" instead.

! src/hotspot/share/runtime/tsan.cpp