Tidy benchmarks (chiefly for Java, and generally for composites)

[jcflack]

This PR fixes a few nits noticed in the Java benchmark tests (old versions in the Java test-suite POM, a /* Failing Test Case */ comment in TestNumeric because the parameters and returns had been declared double instead, and a similar issue in TestArray).

This PR also touches the other PLs and the Makefiles in order to factor out the CREATE TYPE Person that was duplicated in every PL's testcomposites.sql. Now it is created once in the Makefile itself. The simplification benefits the Java test, as now the intended type Person can simply be used in the Java source annotations to generate those functions with the correct signatures, eliminating the need for duplicate CREATE FUNCTION commands in java/testcomposites.sql. For that to work, of course, the type has to exist at the time of the install_jar call.