datatype issues in testsuite

There are a few things in the test suite that I think need fixes:

1) In functions/coalesce01.srx, ?div=0 and ?div=2 should be ?div=0.0 and ?div=2.0 (integer->decimal) because of xsd numeric-divide rules.

2) In aggregates/agg-avg-02.srx, ?avg=2 should be ?avg=2.0 (integer->decimal) because of xsd numeric-divide rules.

3) In aggregates/agg-err-02.srx, ?avg="2."^^decimal should be ?avg="2.0"^^decimal (srx should use canonical lexical form)

(I think this was brought up during a related conversation a few weeks ago, but I couldn't track down a link.)

I believe the first two changes are necessary as the current values seem to contradict the xsd numeric-divide definition. The third change is subjective, but I don't see any reason to prefer the lexical form that ends in a decimal point over the canonical form that requires a digit after the decimal point.

.greg