BUG: Make copies of certain interpolate arguments (GH7295)
closes #7295
On the alt_methods branch in interpolate_1d, make copies if x, y, and new_x don't have their `writeable` attribute set.  It seems a little weird that we need to do this, but it'll work around the issue so that the test can pass, anyway.

any specific tests that need to add (aside from the 32-but failures)
pls add release note in 0.14.1
can u rebase everything always and squash to a single commit

thxs
 Yep, was looking up my "how to rebase and squash" tutorial right now.  I don't think there are any new tests, though.  Are minor and obscure notes like this really worth a release note, though?
 right - forgot the release note then
ok on tests (assume it passes your system!)
 thanks!
