Remove libfuzzer / afl based builds in favor of go 1.18 fuzz testing (#10065)

* Remove libfuzzer / afl based builds in favor of go 1.18 fuzz testing

* rm beacon-fuzz archive

Co-authored-by: prylabs-bulldozer[bot] <58059840+prylabs-bulldozer[bot]@users.noreply.github.com>

BUILD.bazel

@@ -144,15 +144,6 @@ common_files = {
     "//:README.md": "README.md",
 }
 
-string_setting(
-    name = "gotags",
-    build_setting_default = "",
-    values = [
-        "",
-        "libfuzzer",
-    ],
-)
-
 sh_binary(
     name = "prysm_sh",
     srcs = ["prysm.sh"],