Fix for updating datetime value

[peterbae]

Starting from SQL Server 2016, the rounding logic for inserting datetime value has been changed. Instead of uniformly rounding up values normally (<=4 rounds down, >=5 rounds up), the logic present in the getRoundedMilliseconds method shows how the numbers are actually rounded.

The writeRPCDateTime method that gets used during updating a datetimecolumn wasn't correctly reflecting this, and this PR addresses that issue.

[codecov-io]

Codecov Report

Merging #962 into dev will decrease coverage by 0.75%.
The diff coverage is 45.83%.

@@             Coverage Diff              @@
##                dev     #962      +/-   ##
============================================
- Coverage     50.58%   49.83%   -0.76%     
+ Complexity     2918     2847      -71     
============================================
  Files           120      120              
  Lines         27987    28004      +17     
  Branches       4678     4682       +4     
============================================
- Hits          14158    13956     -202     
- Misses        11532    11789     +257     
+ Partials       2297     2259      -38

Flag	Coverage Δ	Complexity Δ
#JDBC42	49.45% <45.83%> (-0.7%)	2811 <2> (-68)
#JDBC43	49.7% <45.83%> (-0.75%)	2843 <2> (-70)

Impacted Files	Coverage Δ	Complexity Δ
...rc/main/java/com/microsoft/sqlserver/jdbc/dtv.java	68.24% <100%> (-0.36%)	0 <0> (ø)
.../microsoft/sqlserver/jdbc/SQLServerConnection.java	46.6% <43.47%> (+0.1%)	343 <2> (+1)	⬆️
...sqlserver/jdbc/SQLServerBulkBatchInsertRecord.java	0% <0%> (-30.72%)	0% <0%> (-18%)
...om/microsoft/sqlserver/jdbc/ReaderInputStream.java	40.65% <0%> (-6.6%)	13% <0%> (-2%)
...oft/sqlserver/jdbc/SQLServerPreparedStatement.java	47.16% <0%> (-6.25%)	189% <0%> (-27%)
.../microsoft/sqlserver/jdbc/SQLServerBulkCommon.java	41.66% <0%> (-5.56%)	3% <0%> (-2%)
...om/microsoft/sqlserver/jdbc/SQLServerBulkCopy.java	49.96% <0%> (-1.67%)	239% <0%> (-15%)
...m/microsoft/sqlserver/jdbc/SQLServerException.java	75.93% <0%> (-1.51%)	31% <0%> (-1%)
...rc/main/java/com/microsoft/sqlserver/jdbc/DDC.java	46.22% <0%> (-1.08%)	110% <0%> (-2%)
...m/microsoft/sqlserver/jdbc/SQLServerResultSet.java	43.21% <0%> (-0.46%)	313% <0%> (-3%)
... and 6 more

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[peterbae]

I re-ran the CI build and it passed: https://dev.azure.com/sqlclientdrivers-ci/mssql-jdbc/_build/results?buildId=278