Whenever we're creating an expression that is typically an rvalue

Whenever we're creating an expression that is typically an rvalue
(e.g., a call, cast, etc.), immediately adjust the expression's type
to strip cv-qualifiers off of all non-class types (in C++) or all
types (in C). This effectively extends my previous fix for PR7463,
which was restricted to calls, to other kinds of expressions within
similar characteristics. I've audited every use of
getNonReferenceType() in the code base, switching to the newly-renamed
getNonLValueExprType() where necessary.

Big thanks to Eli for pointing out just how incomplete my original fix
for PR7463 actually was. We've been handling cv-qualifiers on rvalues
wrong for a very, very long time. Fixes PR7463.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@108253 91177308-0d34-0410-b5e6-96231b3b80d8