[X86] Provide the LSDA pointer with RIP relative addressing if necessary

This makes sure the LSDA pointer isn't truncated to 32 bit.

Make LowerINTRINSIC_WO_CHAIN a member function instead of a static
function, so that it can use the getGlobalWrapperKind method.

This solves the second half of the issues mentioned in PR34720.

Differential Revision: https://reviews.llvm.org/D38343

llvm-svn: 314767