Split memory related methods out of BuilderMethods and move get_param from Cx to Bx

Author: bjorn3

src/librustc_codegen_llvm/abi.rs

@@ -859,4 +859,8 @@ impl AbiBuilderMethods<'tcx> for Builder<'a, 'll, 'tcx> {
     ) {
         ty.apply_attrs_callsite(self, callsite)
     }
+
+    fn get_param(&self, index: usize) -> Self::Value {
+        llvm::get_param(self.llfn(), index as c_uint)
+    }
 }