Increased minimum logcat timeout from 20s to 50s...

...as 20s is often not enough when the device has larger logcat buffer sizes.

Test:  mmm -j32 frameworks/native/cmds/dumpstate/ && adb sync && \
      adb shell /data/nativetest/dumpstate_test/dumpstate_test && \
      adb shell /data/nativetest64/dumpstate_test/dumpstate_test && \
      printf "\n\n#### GOOD NEWS, EVERYONE: ALL TESTS PASSED! ####\n"

Fixes: 70597931

Change-Id: Ie302f46ed405d33bc7411dce28a93949183d4bac