Tweak UI automator runner output format

For uncaught exceptions, output exception message as shortMsg

Change-Id: Ied019d3170a5afc9ebeab8251f66f69d9a9c2282
diff --git a/uiautomator/library/testrunner-src/com/android/uiautomator/testrunner/UiAutomatorTestRunner.java b/uiautomator/library/testrunner-src/com/android/uiautomator/testrunner/UiAutomatorTestRunner.java
index ff3ed69..ef167f9 100644
--- a/uiautomator/library/testrunner-src/com/android/uiautomator/testrunner/UiAutomatorTestRunner.java
+++ b/uiautomator/library/testrunner-src/com/android/uiautomator/testrunner/UiAutomatorTestRunner.java
@@ -162,6 +162,7 @@
         } catch (Throwable t) {
             // catch all exceptions so a more verbose error message can be outputted
             resultPrinter.printUnexpectedError(t);
+            testRunOutput.putString("shortMsg", t.getMessage());
         } finally {
             long runTime = SystemClock.uptimeMillis() - startTime;
             resultPrinter.print(testRunResult, runTime, testRunOutput);