test(csharp/test/Drivers/Snowflake): Correct FLOAT min/max tests in .…

…NET 4.7.2 (apache#1312)

.NET 4.7.2 will round up Double.MaxValue / round down Double.MinValue
when using Double.ToString(), resulting in infinity / -infinity stored
in Snowflake when passed into the INSERT query statement. This rounding
does not occur in .NET 6.0.

This PR corrects that behavior and sends a properly accepted
MaxValue/MinValue string when using .NET 4.7.2.

Notable that when the tests can use prepared statements, issues like
this should cease to happen.

csharp/test/Drivers/Snowflake/ValueTests.cs

@@ -239,6 +239,13 @@ private static string ConvertDoubleToString(double value)
                     return "'-inf'";
                 case double.NaN:
                     return "'NaN'";
+#if NET472
+                // Standard Double.ToString() calls round up the max value, resulting in Snowflake storing infinity
+                case double.MaxValue:
+                    return "1.7976931348623157E+308";
+                case double.MinValue:
+                    return "-1.7976931348623157E+308";
+#endif
                 default:
                     return value.ToString();
             }