Use old assertion text script in precompiled mode

runtime/lib/errors.cc

Index: runtime/lib/errors.cc
diff --git a/runtime/lib/errors.cc b/runtime/lib/errors.cc
index b039efa97257f8575b727c52ababeb0fc6c4af13..75f354d4f94ed60ebee55ff347dd6d845340d156 100644
--- a/runtime/lib/errors.cc
+++ b/runtime/lib/errors.cc
@@ -14,6 +14,15 @@ namespace dart {
 // Scan the stack until we hit the first function in the _AssertionError
 // class. We then return the next frame's script taking inlining into account.
 static RawScript* FindScript(DartFrameIterator* iterator) {
+  if (FLAG_precompiled_runtime) {
+    // The precompiled runtime faces two issues in recovering the correct
+    // assertion text. First, the precompiled runtime does not include
+    // the inlining meta-data so we cannot walk the inline-aware stack trace.
+    // Second, the script text itself is missing so whatever script is returned
+    // from here will be missing the assertion expression text.
+    iterator->NextFrame();  // Skip _AssertionError._checkAssertion frame
+    return Exceptions::GetCallerScript(iterator);
+  }
   StackFrame* stack_frame = iterator->NextFrame();
   Code& code = Code::Handle();
   Function& func = Function::Handle();