Rollup merge of #130734 - Luv-Ray:fix_vfe, r=lcnr

Fix: ices on virtual-function-elimination about principal trait

Extract `load_vtable` function to ensure the `virtual_function_elimination` option is always checked.
It's okay not to use `llvm.type.checked.load` to load the vtable if there is no principal trait.

Fixes #123955
Fixes #124092

compiler/rustc_codegen_ssa/src/mir/intrinsic.rs

@@ -126,7 +126,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     sym::vtable_align => ty::COMMON_VTABLE_ENTRIES_ALIGN,
                     _ => bug!(),
                 };
-                let value = meth::VirtualIndex::from_index(idx).get_usize(bx, vtable);
+                let value = meth::VirtualIndex::from_index(idx).get_usize(bx, vtable, callee_ty);
                 match name {
                     // Size is always <= isize::MAX.
                     sym::vtable_size => {