[TF:XLA] Ensure that deadness_analysis.cc is only linked once

Escaping the transitive dependency on :compilation_passes is impossible:
//tensorflow/compiler/jit:deadness_analysis_test
-> //tensorflow/compiler/jit/kernels:xla_launch_op
-> //tensorflow/compiler/jit:xla_device
-> //tensorflow/compiler/jit:jit_compilation_passes
-> //tensorflow/compiler/jit:compilation_passes

Linking both :compilation_passes and :deadness_analysis_internal into one test
leads to ODR conflicts. Asan complains about them. Just remove the internal
target and add the internal header to the test.

PiperOrigin-RevId: 207546071