[dynamo] Refactor transform() so that instruction translator can be used as a tracing function. [2/n] (#160815)

We are refactoring dynamo code for convert frame so that we can have modularized pieces sharable between different compiler frontends (e.g. torch.compile, precompile and torch.export).

This PR follows the last one which separate out the part to run instruction translator on a given frame and return a DynamoTracerOutput.

The end result is a free function that runs instruction translator indepedently. A follow up diff will wrap the low level function.

Differential Revision: [D80388694](https://our.internmc.facebook.com/intern/diff/D80388694/)

Pull Request resolved: https://github.com/pytorch/pytorch/pull/160815
Approved by: https://github.com/anijain2305
ghstack dependencies: #160814

torch/_dynamo/output_graph.py

@@ -2263,6 +2263,22 @@ class OutputGraph(OutputGraphGuardsState):
         return self.nn_modules[node.target]  # type: ignore[index]
 
 
+class DynamoTracerOutput:
+    error_on_graph_break: bool
+    is_tracing_resume_prologue: bool
+    output_graph: Optional[OutputGraph]
+
+    def __init__(
+        self, tracer: "InstructionTranslatorBase", error: Optional[Any] = None
+    ) -> None:
+        self.error_on_graph_break = tracer.error_on_graph_break
+        self.is_tracing_resume_prologue = tracer.is_tracing_resume_prologue
+        if error:
+            self.output_graph = None
+        else:
+            self.output_graph = tracer.output
+
+
 err_epilogue = (
     "With the current config, we will graph break "
     "(and fall back to eager-mode PyTorch) on all ops "