Remove the unused "fuzzer" build target.

As in aosp/145592, the reason why `dexfuzz-script` added
`$(HOST_CORE_IMG_OUTS)` to its dependencies is that it hardcodes a
check for the existence of the directory
`androidHostOut+"/framework/core.art"` in
`art/tools/dexfuzz/src/dexfuzz/executors/Device.java`.

However, the `core-oj`, `core-libart`, and other
`$(HOST_BOOT_IMAGE_JARS)` have been converted to Soong build. Even when
running "m fuzzer", no files are generated under
`$(HOST_OUT)/framework/core.art`.
Therefore, adding `$(HOST_CORE_IMG_OUTS)` as a dependency for `fuzzer`
is no longer necessary and can be safely removed.

Bug: 339155489
Test: N/A
Change-Id: I0b376e01f2c69d572558492cf9663efd197add90
2 files changed