Adds TEST_MAPPING for Settings > Accessibility unit tests.

This initial TEST_MAPPING file is postsubmit only until we validate
which tests are stable enough to be moved to presubmit and which need
fixes.

Bug: 267225211
Test: atest --test-mapping packages/apps/Settings/src/com/android/settings/accessibility
Change-Id: I5e5f337d4ea7618ab92d3daa5171fd8ee1508c59

src/com/android/settings/accessibility/TEST_MAPPING

@@ -0,0 +1,12 @@
+{
+  "postsubmit": [
+    {
+      "name": "SettingsUnitTests",
+      "options": [
+        {
+          "include-filter": "com.android.settings.accessibility"
+        }
+      ]
+    }
+  ]
+}

tests/unit/src/com/android/settings/accessibility/TEST_MAPPING

@@ -0,0 +1,7 @@
+{
+  "imports": [
+    {
+      "path": "packages/apps/Settings/src/com/android/settings/accessibility/TEST_MAPPING"
+    }
+  ]
+}