Remove dependencies on old iree-tools-xla package

[ScottTodd]

There are references to iree-tools-xla, which was merged into iree-tools-tf along with adoption of StableHLO (see iree-org/iree#13068).

iree-jax/setup.py

Lines 53 to 60 in 584b6c1

	extras_require={
	"xla": [
	get_pinned_package("iree-tools-xla"),
	],
	"test": [
	"lit",
	]
	},

iree-jax/iree/jax/frontend.py

Lines 61 to 63 in 584b6c1

	return iree.compiler.tools.xla.compile_str(hlo_proto,
	input_type=iree.compiler.InputType.XLA,
	**options)

Removing those might just be a matter of switching to newer packages / APIs, or other code changes might be needed.