Revert of [Telemetry] Increase timeout after sending SIGTERM (patchset …

…#2 id:20001 of https://codereview.chromium.org/2568033003/ )

Reason for revert:
Testing to see if it caused the issue on Linux on the waterfall: https://bugs.chromium.org/p/chromium/issues/detail?id=674146

Original issue's description:
> [Telemetry] Increase timeout after sending SIGTERM
>
> To shut down the browser on desktop, we first try to quit the browser normally,
> then send SIGTERM, then wait a while, then send SIGKILL if we still don't see
> that the browser is shut down.
>
> Apparently, with CHROME_HEADLESS=1, we should be getting a .dmp file on
> SIGTERM, but we see no such file.
>
> kbr@ suggests that this may simply be because we're not waiting long enough.
> The best result of this CL would be that we start getting useful stack traces
> from these launch failures.
>
> BUG=catapult:#3074
>
> Review-Url: https://codereview.chromium.org/2568033003
> Committed: https://chromium.googlesource.com/external/github.com/catapult-project/catapult/+/e6e0862c81652393de2dd878322e8c0c1e43d428

TBR=kbr@chromium.org,nednguyen@google.com,eakuefner@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=catapult:#3074

Review-Url: https://codereview.chromium.org/2570413002

telemetry/telemetry/internal/backends/chrome/desktop_browser_backend.py

@@ -616,9 +616,7 @@ def Close(self):
     if self.IsBrowserRunning():
       self._proc.terminate()
       try:
-        # Increased from 5 to increase the likelihood of getting a strack trace.
-        # See https://github.com/catapult-project/catapult/issues/3074.
-        py_utils.WaitFor(lambda: not self.IsBrowserRunning(), timeout=20)
+        py_utils.WaitFor(lambda: not self.IsBrowserRunning(), timeout=5)
         self._proc = None
       except py_utils.TimeoutException:
         logging.warning('Failed to gracefully shutdown.')