Instead of byte-copying the WT_IKEY structure and data, call the standard
underlying supporting function.  Clang is complaining about the internal
page binary search function going off the end of the allocated memory: I
don't see a bug here, but there's no reason to create the WT_IKEY structure
in a non-standard way, and maybe I'm just missing something.
Merge branch 'develop' into avoid-cell-unpack

Conflicts:
	src/btree/rec_split.c