Fix issue 705 by including the possible negative sign

[yitam]

This change is 

[coveralls]

Coverage decreased (-0.03%) to 73.301% when pulling 88f0bcf on yitam:issue705 into 1958cfd on Microsoft:dev.

[codecov-io]

Codecov Report

Merging #732 into dev will decrease coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##              dev     #732      +/-   ##
==========================================
- Coverage   79.02%   78.99%   -0.03%     
==========================================
  Files          25       25              
  Lines        7188     7190       +2     
==========================================
  Hits         5680     5680              
- Misses       1508     1510       +2

Impacted Files	Coverage Δ
...p-7.1.15-src/ext/pdo_sqlsrv/shared/core_stream.cpp
...rojects/php/x86/php-7.1.15-src/ext/sqlsrv/stmt.cpp
...php/x86/php-7.1.15-src/ext/pdo_sqlsrv/pdo_util.cpp
...rojects/php/x86/php-7.1.15-src/ext/sqlsrv/conn.cpp
...php-7.1.15-src/ext/pdo_sqlsrv/shared/core_conn.cpp
...php-7.1.15-src/ext/pdo_sqlsrv/shared/core_util.cpp
...php-7.1.15-src/ext/pdo_sqlsrv/shared/core_sqlsrv.h
...p/x86/php-7.1.15-src/ext/pdo_sqlsrv/pdo_parser.cpp
...x86/php-7.1.15-src/ext/sqlsrv/shared/core_util.cpp
.../php-7.1.15-src/ext/sqlsrv/shared/core_results.cpp
... and 40 more

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[david-puglielli]

Is it not an issue with floats, reals, or bigints?

[yitam]

good point about bigints but not an issue with floats or reals when testing

[yitam]

Fix for #705