Fix the documentation of `dex2oat`'s option `--watchdog-timeout`.

This option's argument is expected to be a duration expressed in
milliseconds, but the documentation says it should be a value
expressed in seconds. Adjust the latter to match the former.

Test: atest art_standalone_dex2oat_tests
Bug: 200251675
Change-Id: Ib6a9fa23d4e8241f93aa180e143090b58b3bbe5c
diff --git a/dex2oat/dex2oat_options.cc b/dex2oat/dex2oat_options.cc
index 988b288..0125f9d 100644
--- a/dex2oat/dex2oat_options.cc
+++ b/dex2oat/dex2oat_options.cc
@@ -295,7 +295,7 @@
           .IntoKey(M::Watchdog)
       .Define("--watchdog-timeout=_")
           .WithType<int>()
-          .WithHelp("Set the watchdog timeout value in seconds.")
+          .WithHelp("Set the watchdog timeout value in milliseconds.")
           .IntoKey(M::WatchdogTimeout)
       .Define("-j_")
           .WithType<unsigned int>()