Integrate IREE at openxla/iree@89a41d9

[simon-camp]

Updates IREE usage to match iree-org/iree@89a41d9 and candidate-20230620.558, respectively.

[lucas-camp]

The libopencm3 build fail with the error undefined reference to _fini. There are two possible solutions I came up with

• Add -specs=nano.specs to arm-none-eabi-gcc.cmake
• Add a stub implementation for void _fini(void) in the customized vector.c

[marbre]

The libopencm3 build fail with the error undefined reference to _fini'. There are two possible solutions I came up with

* Add `-specs=nano.specs` to [arm-none-eabi-gcc.cmake](https://github.com/iml130/iree-bare-metal-arm/blob/68e90077fe637e964d19e9a2354d74cf8caa19a2/build_tools/cmake/arm-none-eabi-gcc.cmake#L48)

* Add a stub implementation for `void _fini(void)` in the customized [vector.c](https://github.com/iml130/iree-bare-metal-arm/blob/main/third_party/libopencm3-custom/vector.c)

Please let us avoid -specs=nano.specs. So if there is no other solution, we can go for a stub implementation, but this should be added with a separate file.

[marbre]

Suggested change

	set(IREE_HAL_EXECUTABLE_PLUGIN_DEFAULTS OFF)
	set(IREE_HAL_EXECUTABLE_PLUGIN_DEFAULTS OFF)
	set(IREE_HAL_EXECUTABLE_PLUGIN_EMBEDDED_ELF ON)

[marbre]

The stub implementation for _fini() was added with #257. I assume this PR fails because IREE_HAL_EXECUTABLE_PLUGIN_EMBEDDED_ELF isn't set. Furthermore, it seems we should use iree_vm_list_get_buffer_view_assign() instead of `iree_vm_list_get_ref_deref(). Sending #258 therefore.