[java] analyzer does not identify implicit return type for functions with ANY TYPE arguments

`CREATE TEMP FUNCTION test(x INT64) AS (x+1)` correctly identifies implicit signature `(INT64 x) -> INT64`.

`CREATE TEMP FUNCTION test(x INT64) AS ('hello world')` correctly identifies implicit signature `(INT64 x) -> STRING`.

`CREATE TEMP FUNCTION test(x ANY TYPE) AS ('hello world')` incorrectly identifies implicit signature `(ANY TYPE x) -> ANY TYPE` where I would expect `(ANY TYPE x) -> STRING`.

`CREATE TEMP FUNCTION test(x ANY TYPE) RETURNS STRING AS ('hello world')` correctly identifies explicit signature `(ANY TYPE x) -> STRING`.

I am running using java api and zeta version `2020.10.1`

Start with the Java API analyzer reproduction described in the issue, using the three temporary-function examples to compare inferred signatures. Done means an ANY TYPE argument with a literal STRING body infers a STRING return type while preserving the existing INT64 and explicit RETURNS behavior.

Written by the indexing model from the issue text.