refactor(maven): Refactor datasource tests (#9745)

...repo/maven2/mysql/mysql-connector-java/maven-metadata.xml

...realm-gradle-plugin/5.13.0/realm-gradle-plugin-5.13.0.pom

..._/jcenter/io/realm/realm-gradle-plugin/maven-metadata.xml

lib/datasource/maven/__fixtures__/metadata-extra.xml

lib/datasource/maven/__fixtures__/metadata-invalid.xml

lib/datasource/maven/__fixtures__/metadata.xml

lib/datasource/maven/__fixtures__/pom.scm-prefix.xml

lib/datasource/maven/__fixtures__/pom.xml

...sql-connector-java/8.0.12/mysql-connector-java-8.0.12.pom

....org/maven2/mysql/mysql-connector-java/maven-metadata.xml

....org/maven2/org/hamcrest/hamcrest-core/maven-metadata.xml

lib/datasource/maven/__snapshots__/index.spec.ts.snap

lib/datasource/maven/index.spec.ts

lib/datasource/maven/util.ts