Replace openxla/iree with iree-org/iree across the project. (#17110)

As part of [moving IREE out of
OpenXLA](https://groups.google.com/g/iree-discuss/c/kdFr4CQwEyY/m/PWJIpZlRBQAJ),
we moved the repository from the [openxla GitHub
organization](https://github.com/openxla) to the [iree-org GitHub
organzation](https://github.com/iree-org).

This updates all occurances of `openxla/iree` to `iree-org/iree` in the
project. Most of these should be handled by redirects.
diff --git a/build_tools/cmake/iree_python.cmake b/build_tools/cmake/iree_python.cmake
index 34875e6..39648a3 100644
--- a/build_tools/cmake/iree_python.cmake
+++ b/build_tools/cmake/iree_python.cmake
@@ -43,7 +43,7 @@
   foreach(_SRC_FILE ${_RULE_SRCS})
     # _SRC_FILE could have other path components in it, so we need to make a
     # directory for it. Ninja does this automatically, but make doesn't. See
-    # https://github.com/openxla/iree/issues/6801
+    # https://github.com/iree-org/iree/issues/6801
     set(_SRC_BIN_PATH "${CMAKE_CURRENT_BINARY_DIR}/${_SRC_FILE}")
     get_filename_component(_SRC_BIN_DIR "${_SRC_BIN_PATH}" DIRECTORY)
     add_custom_command(