Fix KeyCharacterMap overlays by reloading base overlay before applying another overlay.

Add all fields to parcel (mLoadFileName, mLayoutOverlayApplied, mKeysByScanCode, mKeysByUsageCode).
Add all fields to equality operator.
Add tests to libinput_tests.

Bug: 210090260
Test: Manually verified that layout changes correctly.
Test: atest libinput_tests
Change-Id: I1777b87e5c2ce8a0dbd42ad48748ea9e669c9139
diff --git a/libs/input/tests/Android.bp b/libs/input/tests/Android.bp
index 18ab1cb..6ffe851 100644
--- a/libs/input/tests/Android.bp
+++ b/libs/input/tests/Android.bp
@@ -37,6 +37,7 @@
         "libui",
         "libutils",
     ],
+    data: ["data/*.kcm"],
     test_suites: ["device-tests"],
 }
 
@@ -59,5 +60,5 @@
         "libbinder",
         "libui",
         "libbase",
-    ]
+    ],
 }