Adjust testsuite/gcc.dg/tree-ssa/vrp-float-1.c

Adjust testsuite/gcc.dg/tree-ssa/vrp-float-1.c

I missed the -details dump flag, plus I wasn't checking the actual folding.
As a bonus I had flipped the dump file name and the count, so the test
was coming out as unresolved, which I missed because I was only checking
for failures and passes.

Whooops.

gcc/testsuite/ChangeLog:

	* gcc.dg/tree-ssa/vrp-float-1.c: Adjust test so it passes.