Implementation of basic data flow analysis for PowerPC (#212)

* WIP implementation

* * Move flow analysis to dedicated file
* Show string constants inline
* Handle calls to MWCC "sled" helpers which otherwise disrupt flow analysis

* Run cargo insta review

* Apply clippy feedback

* Update more tests.

* Remove std use from ppc flow analysis

* Try to make wasm build work again

* More test changes

* Probably last wasm fix

* Formatting

* Fix WASM

* One more clippy thing

* Fixed display of float constants in a LFS or LFD instruction in case where there is a branch to the subsequent instruction with a different register value.

* On lines with a reloc, only hide Symbol type data flow values rather than all data flow values.

* Formatting

objdiff-gui/src/views/diff.rs

@@ -281,6 +281,24 @@ pub fn diff_view_ui(
                     })
                 });
             }
+
+            // Only need to check the first Object. Technically the first could not have a flow analysis
+            // result while the second does but we don't want to waste space on two separate checkboxes.
+            if state.current_view == View::FunctionDiff
+                && result
+                    .first_obj
+                    .as_ref()
+                    .is_some_and(|(first, _)| first.has_flow_analysis_result())
+            {
+                let mut value = diff_config.show_data_flow;
+                if ui
+                    .checkbox(&mut value, "Show data flow")
+                    .on_hover_text("Show data flow analysis results in place of register names")
+                    .clicked()
+                {
+                    ret = Some(DiffViewAction::SetShowDataFlow(value));
+                }
+            }
         } else if column == 1 {
             // Right column