Fix InTouchMode is not consistent between WMS and InputFlinger

Use getInTouchMode/setInTouchMode to access InTouchMode in WMS.

Test: atest TouchModeFocusChangeTest
Bug: 148002313
Change-Id: Iebea007f638624706ed91b6c17dcc73506d779ac
diff --git a/services/core/java/com/android/server/wm/Session.java b/services/core/java/com/android/server/wm/Session.java
index de7f9e4..ab1f34a 100644
--- a/services/core/java/com/android/server/wm/Session.java
+++ b/services/core/java/com/android/server/wm/Session.java
@@ -238,16 +238,12 @@
 
     @Override
     public void setInTouchMode(boolean mode) {
-        synchronized (mService.mGlobalLock) {
-            mService.mInTouchMode = mode;
-        }
+        mService.setInTouchMode(mode);
     }
 
     @Override
     public boolean getInTouchMode() {
-        synchronized (mService.mGlobalLock) {
-            return mService.mInTouchMode;
-        }
+        return mService.getInTouchMode();
     }
 
     @Override