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/symbol_diff.rs

@@ -79,6 +79,8 @@ pub enum DiffViewAction {
     SetMapping(usize, usize),
     /// Set the show_mapped_symbols flag
     SetShowMappedSymbols(bool),
+    /// Set the show_data_flow flag
+    SetShowDataFlow(bool),
 }
 
 #[derive(Debug, Clone, Default, Eq, PartialEq)]
@@ -350,6 +352,12 @@ impl DiffViewState {
             DiffViewAction::SetShowMappedSymbols(value) => {
                 self.symbol_state.show_mapped_symbols = value;
             }
+            DiffViewAction::SetShowDataFlow(value) => {
+                let Ok(mut state) = state.write() else {
+                    return;
+                };
+                state.config.diff_obj_config.show_data_flow = value;
+            }
         }
     }