Move external MultiTouch test into InputMapperUnitTest

This test is broken because it relies on an incorrect ACTION_CANCEL
event being generated. Move this test over to the new
InputMapperUnitTest infra before fixing it in subsequent CLs.

Bug: 378308551
Test: TEST=inputflinger_tests; m $TEST && $ANDROID_HOST_OUT/nativetest64/$TEST/$TEST
Flag: TEST_ONLY
Change-Id: I016fb66f7fcbe957cd5b6e8ca86513cb8c372cd3