Remove unused coverage code (#3118)

All tests pass with this code removed - it is not used.

go/private/BUILD.bazel

@@ -76,7 +76,6 @@ bzl_library(
         "//go/private/actions:asm",
         "//go/private/actions:binary",
         "//go/private/actions:compile",
-        "//go/private/actions:cover",
         "//go/private/actions:link",
         "//go/private/actions:pack",
         "//go/private/actions:stdlib",

go/private/actions/BUILD.bazel

@@ -60,16 +60,6 @@ bzl_library(
     ],
 )
 
-bzl_library(
-    name = "cover",
-    srcs = ["cover.bzl"],
-    visibility = ["//go:__subpackages__"],
-    deps = [
-        "//go/private:providers",
-        "@bazel_skylib//lib:structs",
-    ],
-)
-
 bzl_library(
     name = "link",
     srcs = ["link.bzl"],

go/private/context.bzl

@@ -483,7 +483,6 @@ def go_context(ctx, attr = None):
         asm = toolchain.actions.asm,
         binary = toolchain.actions.binary,
         compile = toolchain.actions.compile,
-        cover = toolchain.actions.cover,
         link = toolchain.actions.link,
         pack = toolchain.actions.pack,
 

go/private/go_toolchain.bzl

@@ -21,7 +21,6 @@ load("//go/private/actions:archive.bzl", "emit_archive")
 load("//go/private/actions:asm.bzl", "emit_asm")
 load("//go/private/actions:binary.bzl", "emit_binary")
 load("//go/private/actions:compile.bzl", "emit_compile")
-load("//go/private/actions:cover.bzl", "emit_cover")
 load("//go/private/actions:link.bzl", "emit_link")
 load("//go/private/actions:pack.bzl", "emit_pack")
 load("//go/private/actions:stdlib.bzl", "emit_stdlib")
@@ -40,7 +39,6 @@ def _go_toolchain_impl(ctx):
             asm = emit_asm,
             binary = emit_binary,
             compile = emit_compile,
-            cover = emit_cover,
             link = emit_link,
             pack = emit_pack,
             stdlib = emit_stdlib,