Do not register JupiterTestEngine in junit-jupiter-migrationsupport

Prior to this commit, the JUnit 4 Migration Support module (i.e.,
junit-jupiter-migrationsupport) incorrectly registered the
JupiterTestEngine via Java's ServiceLoader mechanism.

This was obviously the result of a copy-n-paste error that occurred
when the junit-jupiter-migrationsupport Gradle project was created.

This commit fixes this issue by deleting the
org.junit.platform.engine.TestEngine file in
src/main/resources/META-INF/services.

Fixes: #1148

Author: sbrannen