Remove ~MaybeHandle and statically assert that handles are trivially copyable

Remove ~MaybeHandle and statically assert that handles are trivially copyable

While investigating http://crbug.com/457078#c79, I noticed that
MaybeHandle has an unecessary user provided destructor. On most
platforms, this means that MaybeHandle will be passed by hidden
reference. Remove the destructor so that it can be passed in registers
when possible, and statically assert that these objects are trivially
copyable so this doesn't regress.

R=jochen@chromium.org,machenbach@chromium.org
BUG=chromium:457078

[jochen (gone - plz use gerrit), 2017-01-13 18:51:29]

jochen@chromium.org changed reviewers:
+ yangguo@chromium.org

[jochen (gone - plz use gerrit), 2017-01-13 18:51:29]

Yang is a better reviewer for this

[Yang, 2017-01-17 12:40:15]

On 2017/01/13 18:51:29, jochen wrote:
> Yang is a better reviewer for this

lgtm.

[Reid Kleckner, 2017-01-17 19:30:59]

The CQ bit was checked by rnk@chromium.org

[commit-bot: I haz the power, 2017-01-17 19:31:02]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-01-17 19:34:28]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-01-17 19:34:29]

Try jobs failed on following builders:
  v8_linux64_avx2_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_avx2_rel_ng/buil...)
  v8_linux64_gyp_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_gyp_rel_ng/build...)
  v8_linux_arm64_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_arm64_rel_ng/build...)
  v8_linux_gcc_compile_rel on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_gcc_compile_rel/bu...)

[agrieve, 2017-02-28 03:31:41]

On 2017/01/17 19:34:29, commit-bot: I haz the power wrote:
> Try jobs failed on following builders:
>   v8_linux64_avx2_rel_ng on master.tryserver.v8 (JOB_FAILED,
>
http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_avx2_rel_ng/buil...)
>   v8_linux64_gyp_rel_ng on master.tryserver.v8 (JOB_FAILED,
>
http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_gyp_rel_ng/build...)
>   v8_linux_arm64_rel_ng on master.tryserver.v8 (JOB_FAILED,
>
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_arm64_rel_ng/build...)
>   v8_linux_gcc_compile_rel on master.tryserver.v8 (JOB_FAILED,
>
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_gcc_compile_rel/bu...)

Wondering if this is still a valid change?

[Reid Kleckner, 2017-03-01 22:14:50]

On 2017/02/28 03:31:41, agrieve wrote:
> On 2017/01/17 19:34:29, commit-bot: I haz the power wrote:
> > Try jobs failed on following builders:
> >   v8_linux64_avx2_rel_ng on master.tryserver.v8 (JOB_FAILED,
> >
>
http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_avx2_rel_ng/buil...)
> >   v8_linux64_gyp_rel_ng on master.tryserver.v8 (JOB_FAILED,
> >
>
http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_gyp_rel_ng/build...)
> >   v8_linux_arm64_rel_ng on master.tryserver.v8 (JOB_FAILED,
> >
>
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_arm64_rel_ng/build...)
> >   v8_linux_gcc_compile_rel on master.tryserver.v8 (JOB_FAILED,
> >
>
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_gcc_compile_rel/bu...)
> 
> Wondering if this is still a valid change?

Probably, but it looks like V8's toolchains don't like static_assert. I haven't
had time to get back and fix this.