Make grpc-java work with bazel HEAD

Symbols such as java_* and ProtoInfo now must be loaded from their
starlark equivalents.

api/BUILD.bazel

@@ -1,3 +1,4 @@
+load("@rules_java//java:java_library.bzl", "java_library")
 load("@rules_jvm_external//:defs.bzl", "artifact")
 
 java_library(

context/BUILD.bazel

@@ -1,3 +1,5 @@
+load("@rules_java//java:java_library.bzl", "java_library")
+
 java_library(
     name = "context",
     visibility = ["//visibility:public"],

core/BUILD.bazel

@@ -1,3 +1,4 @@
+load("@rules_java//java:java_library.bzl", "java_library")
 load("@rules_jvm_external//:defs.bzl", "artifact")
 
 java_library(

java_grpc_library.bzl

@@ -1,5 +1,6 @@
 """Build rule for java_grpc_library."""
 
+load("@com_google_protobuf//bazel/common:proto_info.bzl", "ProtoInfo")
 load("@rules_java//java:defs.bzl", "JavaInfo", "JavaPluginInfo", "java_common")
 
 _JavaRpcToolchainInfo = provider(

netty/BUILD.bazel

@@ -1,3 +1,4 @@
+load("@rules_java//java:java_library.bzl", "java_library")
 load("@rules_jvm_external//:defs.bzl", "artifact")
 
 java_library(

protobuf-lite/BUILD.bazel

@@ -1,3 +1,4 @@
+load("@rules_java//java:java_library.bzl", "java_library")
 load("@rules_jvm_external//:defs.bzl", "artifact")
 
 java_library(

protobuf/BUILD.bazel

@@ -1,3 +1,4 @@
+load("@rules_java//java:java_library.bzl", "java_library")
 load("@rules_jvm_external//:defs.bzl", "artifact")
 
 java_library(

stub/BUILD.bazel

@@ -1,3 +1,4 @@
+load("@rules_java//java:java_library.bzl", "java_library")
 load("@rules_jvm_external//:defs.bzl", "artifact")
 
 java_library(

util/BUILD.bazel

@@ -1,3 +1,4 @@
+load("@rules_java//java:java_library.bzl", "java_library")
 load("@rules_jvm_external//:defs.bzl", "artifact")
 
 java_library(