Disable slow decay warning for one test in tests/chebfun/test_innerProduct.m.
Disable slow decay warning for one test in tests/chebfun/test_innerProduct.m.

The warning is bogus in this case, but until we get a better algorithm
for assessing decay rates, there's not much else we can do...

ilovejs/chebfun,asgeirbirkis/chebfun,alshedivat/chebfun