[TVMScript] Preserve traceback across TVMScript parsing (#15824)

Prior to this commit, exceptions raised during the parsing of
TVMScript would be caught and replaced with a new exception.  While
this does allow the TVMScript location of the error to be included in
the exception, it also removes the stack trace of the original error.
This commit updates the `Parser.report_error` function to provide the
original stack trace alongside the updated exception object.

Author: Lunderberg

python/tvm/script/parser/core/parser.py

@@ -522,7 +522,18 @@ def report_error(
             msg = "KeyError: " + str(err)
         else:
             msg = str(err)
-        self.diag.error(node, msg)
+
+        try:
+            self.diag.error(node, msg)
+        except Exception as diag_err:
+            # Calling self.diag.error is guaranteed to throw an
+            # exception.  When shown to a user, this error should
+            # reference the point of error within the provided
+            # TVMScript.  However, when caught in pdb, the full
+            # traceback should be available for debugging.
+            if isinstance(err, Exception):
+                diag_err = diag_err.with_traceback(err.__traceback__)
+            raise diag_err
 
     def visit(self, node: doc.AST) -> None:
         """The general visiting method.