devtools: Handle the setBreakpoint message. (#41925)

Listen for `setBreakpoint` on `debugger.js` and add the relevant WebIDLs
and Servo counterparts to trigger this event and notify SpiderMonkey.

Implement `find_source` for `SourceManager` and `find_offset` for
`SourceActor`.

Testing: Manual testing and `./mach test-devtools` (note, the latter
seems to have some failing tests, we are investigating this, but this
patch doesn't add any new failure).
Fixes: Part of #36027

---------

Signed-off-by: eri <eri@igalia.com>
Co-authored-by: atbrakhi <atbrakhi@igalia.com>

components/script/script_thread.rs

@@ -2162,6 +2162,14 @@ impl ScriptThread {
                     result_sender,
                 );
             },
+            DevtoolScriptControlMsg::SetBreakpoint(spidermonkey_id, script_id, offset) => {
+                self.debugger_global.fire_set_breakpoint(
+                    CanGc::from_cx(cx),
+                    spidermonkey_id,
+                    script_id,
+                    offset,
+                );
+            },
         }
     }