[analyzer] Fix a crash that occurs when processing an rvalue array.

When processing ArrayToPointerDecay, we expect the array to be a location, not a LazyCompoundVal.
Special case the rvalue arrays by using a location to represent them. This case is handled similarly
elsewhere in the code.

Fixes PR16206.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@183359 91177308-0d34-0410-b5e6-96231b3b80d8