Wrong union-by-value argument passing in JRuby #9329

Failures:

  1) Union by_value should correctly align/write a float value to union_float_test_t by value
     Failure/Error: expect((@u[name] - ByValueLibTest.send("#{uni}_val_align_#{k}", @u)).abs).to be < 0.00001

       expected: < 1.0e-05
            got:   2.71598704641059e+36
     # ./spec/ffi/union_spec.rb:141:in 'block in UnionSpec'

  2) Union by_value should correctly align/write a double value to union_float_test_t by value
     Failure/Error: expect((@u[name] - ByValueLibTest.send("#{uni}_val_align_#{k}", @u)).abs).to be < 0.00001

       expected: < 1.0e-05
            got:   2.0000000000001
     # ./spec/ffi/union_spec.rb:141:in 'block in UnionSpec'

  3) Union by_value should read a float value from memory of union_float_test_t by value
     Failure/Error: expect((@u[name] - val).abs).to be < 0.00001

       expected: < 1.0e-05
            got:   3.444
     # ./spec/ffi/union_spec.rb:152:in 'block in UnionSpec'

  4) Union by_value should read a double value from memory of union_float_test_t by value
     Failure/Error: expect((@u[name] - val).abs).to be < 0.00001

       expected: < 1.0e-05
            got:   2.0000000000001
     # ./spec/ffi/union_spec.rb:152:in 'block in UnionSpec'

Failures:

  1) Union by_value should return a union of doubles by value
     Failure/Error: expect(u[:coord][:x]).to eq(1.5)

       expected: 1.5
            got: 1.4978809957e-313

       (compared using ==)
     # ./spec/ffi/union_spec.rb:162:in 'block in UnionSpec'

  2) Union by_value should pass a union of doubles by value
     Failure/Error: expect(ByValueLibTest.union_double_get_x(u)).to eq(10.0)

       expected: 10.0
            got: 1.4979119926e-313

       (compared using ==)
     # ./spec/ffi/union_spec.rb:170:in 'block in UnionSpec'

  3) Union by_value should pass and return a union of doubles by value
     Failure/Error: expect(r[:coord][:x]).to eq(1.5)

       expected: 1.5
            got: 1.49791841507e-313

       (compared using ==)
     # ./spec/ffi/union_spec.rb:180:in 'block in UnionSpec'

  4) Union by_value should access union doubles via array field
     Failure/Error: expect(u[:v].to_a).to eq([1.5, 2.5, 3.5, 4.5])

       expected: [1.5, 2.5, 3.5, 4.5]
            got: [1.4979237569e-313, 1.38697476291614e-309, 1.78e-321, 1.386978271489887e-309]

       (compared using ==)
     # ./spec/ffi/union_spec.rb:188:in 'block in UnionSpec'