Fix Web API error masking in production mode

[skolodyazhnyy]

Q	A
Bug fix?	yes
New feature?	no
BC breaks?	no
Deprecations?	no
Tests pass?	yes

In this PR I have changed exception masking for Web API. Current implementation hide Stack trace and may cause fatal errors for custom exception types because it tries to reinstantiate exception with different messages. In my proposed implementation I'm wrapping original exception into WebapiExceptionReport which carry reportId in the property and original exception as previous exception.

Ways to reproduce:

A. Losing stack trace

1. Make sure developer mode disabled
2. Make an API query where a critical exception occurs. You may want to change API implementation in order to force an exception.

Expected result
I can see WebAPI report ID in the API response and exception stack trace in the log file.

Actual result
I can see WebAPI report ID in the API response but exception stack trace always refer to crtitical method call:

[2015-11-14 00:14:31] main.CRITICAL: exception 'ReflectionException' with message 'Report ID: webapi-56467ce7f2048; Message: Class string does not exist' in /var/www/lib/internal/Magento/Framework/Webapi/ErrorProcessor.php:194
Stack trace:
#0 /var/www/lib/internal/Magento/Framework/Webapi/ErrorProcessor.php(139): Magento\Framework\Webapi\ErrorProcessor->_critical(Object(ReflectionException))
#1 /var/www/app/code/Magento/Webapi/Controller/Rest.php(163): Magento\Framework\Webapi\ErrorProcessor->maskException(Object(ReflectionException))
#2 /var/www/var/generation/Magento/Webapi/Controller/Rest/Interceptor.php(24): Magento\Webapi\Controller\Rest->dispatch(Object(Magento\Framework\App\Request\Http))
#3 /var/www/lib/internal/Magento/Framework/App/Http.php(115): Magento\Webapi\Controller\Rest\Interceptor->dispatch(Object(Magento\Framework\App\Request\Http))
#4 /var/www/lib/internal/Magento/Framework/App/Bootstrap.php(258): Magento\Framework\App\Http->launch()
#5 /var/www/index.php(45): Magento\Framework\App\Bootstrap->run(Object(Magento\Framework\App\Http))
#6 {main} [] []

B. Fatal error during exception creation

1. Make sure developer mode is disabled
2. Define a new exception type which has custom constructor, for example:

class UnexpectedPropertyTypeException extends Exception
{
    public function __construct(array $expectedTypes, $actualType)
    {
        parent::__construct(sprintf("Unexpected property type %s, expected types: %s", $actualType, implode(', ', $expectedTypes)));
    }
}

1. Throw this exception somewhere in your API implementation

Expected result
We should see exception message in the log

Actual result
Fatal error: Argument 1 passed to ...::__construct() must be of the type array, string given

[Vinai]

Thank you for your contribution!
All tests pass, the contributor license agreement is signed, code looks okay: ready for review by core team.

[vrann]

Change makes sense, thanks for contribution!

[okorshenko]

@skolodyazhnyy, because of integrity tests failure, we will modify the code of this PR. But thank you for contribution.

[okorshenko]

@skolodyazhnyy your Pull Request merged to develop branch. Thank you for contribution!