[FIX] Introduce different SAI objects for scalar and memory accesses

  Even if a scalar and memory access have the same base pointer, we cannot use
  one SAI object as the type but also the number of dimensions are wrong. For
  the attached test case this caused a crash in the invariant load hoisting,
  though it could cause various other problems too.

This fixes bug 25428 and a execution time bug in MallocBench/cfrac.

Reported-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
llvm-svn: 252422