Add unit tests for LockSettingsService

Add infrastructure and first sets of unit tests for LockSettingsService

Bug: 33126408
Test: runtest frameworks-services -c com.android.server.LockSettingsServiceTests
Change-Id: I4f3b7f6eaef7122f72b06bd11ce49134a093fe35
diff --git a/services/core/java/com/android/server/LockSettingsShellCommand.java b/services/core/java/com/android/server/LockSettingsShellCommand.java
index f72663a..e131251 100644
--- a/services/core/java/com/android/server/LockSettingsShellCommand.java
+++ b/services/core/java/com/android/server/LockSettingsShellCommand.java
@@ -77,7 +77,8 @@
             }
             return 0;
         } catch (Exception e) {
-            getErrPrintWriter().println("Error while executing command: " + e);
+            getErrPrintWriter().println("Error while executing command: " + cmd);
+            e.printStackTrace(getErrPrintWriter());
             return -1;
         }
     }