Define non-intrinsic instructions for vector min, max, sqrt, rsqrt, and rcp,

Define non-intrinsic instructions for vector min, max, sqrt, rsqrt, and rcp,
in addition to the intrinsic forms. Add spill-folding entries for these new
instructions, and for the scalar min and max instrinsic instructions which
were missing. And add some preliminary ISelLowering code for using the new
non-intrinsic vector sqrt instruction, and fneg and fabs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@38478 91177308-0d34-0410-b5e6-96231b3b80d8