Avoid emitting canonical labels into repo rules

As long as bazelbuild#20722 isn't resolved, the canonical name for the given
apparent name can change without the repo rule being refetched.

tools/build_defs/repo/http.bzl

@@ -192,8 +192,6 @@ def _http_file_impl(ctx):
     return _update_integrity_attr(ctx, _http_file_attrs, download_info)
 
 _HTTP_JAR_BUILD = """\
-load("{rules_java_defs}", "java_import")
-
 package(default_visibility = ["//visibility:public"])
 
 java_import(
@@ -226,7 +224,6 @@ def _http_jar_impl(ctx):
     ctx.file("WORKSPACE", "workspace(name = \"{name}\")".format(name = ctx.name))
     ctx.file("jar/BUILD", _HTTP_JAR_BUILD.format(
         file_name = downloaded_file_name,
-        rules_java_defs = str(Label("@rules_java//java:defs.bzl")),
     ))
 
     return _update_integrity_attr(ctx, _http_jar_attrs, download_info)

tools/build_defs/repo/jvm.bzl

@@ -288,11 +288,6 @@ def jvm_maven_import_external(
     srcjar_urls = kwargs.pop("srcjar_urls", None)
 
     rule_name = kwargs.pop("rule_name", "java_import")
-    rules_java_defs = str(Label("@rules_java//java:defs.bzl"))
-    rule_load = kwargs.pop(
-        "rule_load",
-        'load("{}", "java_import")'.format(rules_java_defs),
-    )
 
     if fetch_sources:
         src_coordinates = struct(