Split the object test into smaller tests (get/set/delete/hasOwnProperty)

[romandev]

This change breaks the object test into smaller tests for the following
reasons:

• Smaller tests are better than very large one. (e.g. readability)
• Before this patch, we have missed some test cases. For example,
  there are four overloading versions of the deleteProperty() method,
  but we haven't tested them all until now.

[romandev]

@mhdawson PTAL

[mhdawson]

Overall LGTM. I'm on vacation for the next week so I'll look at landing when I get back or if another reviewer takes a look between now and then they can go head earlier.

[romandev]

@mhdawson Thank you for review and I'll request another reviewer. Have a good vacation :)

[romandev]

@addaleax Could you please review this patch if you have a minute?

[mhdawson]

Ran the tests locally on linux and I got this failure:

Starting test suite

Running test 'arraybuffer'
Running test 'asyncworker'
Running test 'buffer'
Running test 'error'
Running test 'external'
Running test 'function'
Running test 'name'
Running test 'object/delete_property'
Running test 'object/get_property'
Running test 'object/has_own_property'
Running test 'object/object'
Running test 'object/set_property'
Tests aborted with SIGSEGV
npm ERR! Test failed.  See above for more details.

With this PR backed out the tests ran ok.

@romandev can you take a look. You can run the tests with npm-test

[romandev]

@mhdawson Done. I've just fixed the error. Thank you!

[mhdawson]

@romandev thanks, landed as e90a80b