* Correctly delete TypeHandles in AsmParser. In addition to not leaking
memory, this prevents a bug that could have occurred when a type got
resolved that the constexpr was using
* Check for errors in the AsmParser instead of hitting assertion failures
deep in the code
* Simplify the interface to the ConstantExpr class, removing unneccesary
parameters to the ::get* methods.
* Rename the 'getelementptr' version of ConstantExpr::get to
ConstantExpr::getGetElementPtr
llvm-svn: 3161