TouchExplorerTest: fix run error.

This line should've been removed long ago because we don't even use the object it declares, but it only recently started to throw an exception. Bug: 194359067
This was fixed in master, but not S.
Test: atest FrameworksServicesTests:TouchExplorerTest

Change-Id: I388edfc5689584b8def7ef421a0bd9be89b71d5b
(cherry picked from commit 2ce8b0c808)

services/tests/servicestests/src/com/android/server/accessibility/gestures/TouchExplorerTest.java

@@ -145,7 +145,6 @@ public class TouchExplorerTest {
         }
         mContext = InstrumentationRegistry.getContext();
         mTouchSlop = ViewConfiguration.get(mContext).getScaledTouchSlop();
-        AccessibilityManagerService ams = new AccessibilityManagerService(mContext);
         mCaptor = new EventCaptor();
         mHandler = new TestHandler();
         mTouchExplorer = new TouchExplorer(mContext, mMockAms, null, mHandler);