This commit makes all of the recommended changes to use the `testing`
package helper functions instead of doing the equivalent longhand
versions of the same thing.
This change was needed in order to properly detect errors, as the code
would previously skip running `tenv` stating that it had been deprecated
in favor of `usetesting`.
Signed-off-by: Enji Cooper <yaneurabeya@gmail.com>
The io/ioutil package has been deprecated as of Go 1.16, see
https://golang.org/doc/go1.16#ioutil. This commit replaces the existing
io/ioutil functions with their new definitions in io and os packages.
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>