[JAVA] Fix 3.1 generation for composed schema's with object type

[g-getsov]

Composed schema request bodies (using oneOf, anyOf, allOf) with type:object currently fall within an edge case which causes generation to fail and in place where we should be generating ParamName or Type ParamName we instead get UNKNOWN_PARAM_NAME.

Example of bad generation

/*
   * @param UNKNOWN_PARAM_NAME  (optional)
   * @throws ApiException if fails to make API call
   */
  public void petsPatch( UNKNOWN_PARAM_NAME) throws ApiException {
    Object localVarPostBody = UNKNOWN_PARAM_NAME;

The additional check for composed schema's catches this edge case and ensures that the generation is correct

  /*
   * @param petsPatchRequest  (optional)
   * @throws ApiException if fails to make API call
   */
  public void petsPatch(PetsPatchRequest petsPatchRequest) throws ApiException {
    Object localVarPostBody = petsPatchRequest;

The generation works fine when the type is omitted (supported v3.1+) and now with the fix it also works when the type:object is present

I've added a test that tests the generation for a schema containing both requestBody objects with and without type

@bbdouglas @sreeshas @jfiala @lukoyanov @cbornet @jeff9finger @karismann @Zomzog @lwlee2608 @martin-mfg

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[wing328]

thanks for the fix, which looks good to me