Issue#2550 - Fixed getGeneratedKeys functionality for execute API

[machavan]

Description:

The execute API for INSERT was not reading off the explicit TDS_DONE token that actually contains the update count returned by the server. As a result, it was not able to correctly report back the update count for getUpdateCount and also the subsequent resultsets on getMoreResults.

Note that this works correctly for excecuteUpdate API.

Testing:

• All existing tests pass
• Introduced a number of tests testing various combinations of execute/executeUpdate API, INSERT/UPDATE/DELETE/MERGE DML operations, followed by explicit SELECT statement or getGeneratedKeys call.

[codecov]

Codecov Report

Attention: Patch coverage is 80.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 51.26%. Comparing base (ae462f9) to head (18c96b5).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...m/microsoft/sqlserver/jdbc/SQLServerStatement.java	75.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #2554      +/-   ##
============================================
+ Coverage     50.99%   51.26%   +0.27%     
- Complexity     3911     3971      +60     
============================================
  Files           147      147              
  Lines         33456    33458       +2     
  Branches       5604     5605       +1     
============================================
+ Hits          17060    17153      +93     
+ Misses        13992    13925      -67     
+ Partials       2404     2380      -24     

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[tkyc]

Internal tests pass