Fix crash related to zend_hash_internal_pointer_reset

[yukiwongky]

Previous parse_param_array utilizes zend_hash_* functions for iterating through the parameters passed into sqlsrv_query or sqlsrv_prepare. These zend_hash_* functions alter the internal pointer in the array directly. This is incorrect because the user may be using the internal pointer for other purposes.

For example:

$params = array(array(1, SQLSRV_PARAM_IN, SQLSRV_PHPTYPE_INT, SQLSRV_SQLTYPE_INT), array('BLAH', SQLSRV_PARAM_OUT, SQLSRV_PHPTYPE_FLOAT));
$direction1 = next($params[0]);    // this changes the internal pointer to point to SQLSRV_PARAM_IN
$stmt = sqlsrv_query($conn, $tsql, $params);    // sqlsrv_query calls zend_hash_* functions to iterate through each array in $params; the internal pointers of the array inside $params now point SQLSRV_SQLTYPE_INT and SQLSRV_PHPTYPE_FLOAT for $params[0] and $params[1] respectively

$direction1 = current($params[0]);    // user still expects the internal pointer to point to SQLSRV_PARAM_IN, however since sqlsrv_query uses the internal pointer direct, now the internal pointer points to SQLSRV_SQLTYPE_INT

To avoid working directly with the array internal pointer, use zend_hash_*_ex functions instead. pos acts as a temporary internal pointer so we don't have alter the actual internal pointer.

This change is 

[coveralls]

Coverage remained the same at 72.504% when pulling 0c0882b on v-kaywon:internalPointerReset into b3f2015 on Microsoft:dev.

[codecov-io]

Codecov Report

Merging #634 into dev will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##              dev     #634   +/-   ##
=======================================
  Coverage   77.13%   77.13%           
=======================================
  Files          25       25           
  Lines        7317     7317           
=======================================
  Hits         5644     5644           
  Misses       1673     1673

Impacted Files	Coverage Δ
...rojects/php/x86/php-7.1.12-src/ext/sqlsrv/stmt.cpp	87.77% <0%> (ø)	⬆️

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