Provide a template for call to File::Temp::tempfile().

Provide a template for call to File::Temp::tempfile().

tempfile() with template gives a file in the current directory.
tempfile() without template gives a file in /tmp.  These may be on different
kinds of filesystems (in the instant case, the former was on ext2, the latter
on ext4) with different characteristics with respect to high-resolution
timing.

Originally reported at:
https://rt.cpan.org/Public/Bug/Display.html?id=116127#txn-1674171