Dynamically add STYLUS source for multi-touch devices

Since we cannot tell definitively whether a multi-touch device that
supports MT_TOOL_TYPE will ever report MT_TOOL_PEN, we default to
configuring the source of such a device not not use SOURCE_STYLUS, and
it to events dynamically if it ever produces a stylus event.

Bug: 246991366
Test: atest inputflinger_tests
Change-Id: I70cc15f8f354e3fc876024d194a6f320fabd6d2c
diff --git a/services/inputflinger/reader/mapper/MultiTouchInputMapper.cpp b/services/inputflinger/reader/mapper/MultiTouchInputMapper.cpp
index 8e757a5..ccff353 100644
--- a/services/inputflinger/reader/mapper/MultiTouchInputMapper.cpp
+++ b/services/inputflinger/reader/mapper/MultiTouchInputMapper.cpp
@@ -200,8 +200,7 @@
 }
 
 bool MultiTouchInputMapper::hasStylus() const {
-    return mMultiTouchMotionAccumulator.hasStylus() || mTouchButtonAccumulator.hasStylus() ||
-            shouldSimulateStylusWithTouch();
+    return mTouchButtonAccumulator.hasStylus() || shouldSimulateStylusWithTouch();
 }
 
 bool MultiTouchInputMapper::shouldSimulateStylusWithTouch() const {