hterm: avoid %T in date format
hterm: avoid %T in date format

Although %T works in macOS & Linux, it doesn't on Windows.
Expand it into its equiv %H:%M:%S so it works everywhere.

Change-Id: Ic8d3f34fe71fd98ee8fff1fddd50d964eafee5a3
Reviewed-on: https://chromium-review.googlesource.com/c/1467541
Reviewed-by: Vitaliy Shipitsyn <6f51537d61e46a00bf958b60dbef5b5870c2bf22@google.com>
Tested-by: Mike Frysinger <8f3f75c74bd5184edcfa6534cab3c13a00a2f794@chromium.org>

chromium/hterm,chromium/hterm,chromium/hterm,chromium/hterm