Do not use constraints from bazel_tools

Fixes #1953

Author: limdor

toolchains/BUILD

@@ -56,13 +56,13 @@ toolchain(
     name = "rbe_container_cc_toolchain",
     exec_compatible_with = [
         "@io_bazel_rules_docker//platforms:run_in_container",
-        "@bazel_tools//platforms:x86_64",
-        "@bazel_tools//platforms:linux",
+        "@platforms//cpu:x86_64",
+        "@platforms//os:linux",
         "@bazel_tools//tools/cpp:clang",
     ],
     target_compatible_with = [
-        "@bazel_tools//platforms:linux",
-        "@bazel_tools//platforms:x86_64",
+        "@platforms//os:linux",
+        "@platforms//cpu:x86_64",
     ],
     toolchain = "@buildkite_config//cc:cc-compiler-k8",
     toolchain_type = "@bazel_tools//tools/cpp:toolchain_type",

toolchains/docker/BUILD

@@ -42,7 +42,7 @@ docker_toolchain(
 toolchain(
     name = "default_linux_toolchain",
     target_compatible_with = [
-        "@bazel_tools//platforms:linux",
+        "@platforms//os:linux",
     ],
     toolchain = "@docker_config//:toolchain",
     toolchain_type = ":toolchain_type",
@@ -51,7 +51,7 @@ toolchain(
 toolchain(
     name = "default_windows_toolchain",
     target_compatible_with = [
-        "@bazel_tools//platforms:windows",
+        "@platforms//os:windows",
     ],
     toolchain = "@docker_config//:toolchain",
     toolchain_type = ":toolchain_type",
@@ -60,7 +60,7 @@ toolchain(
 toolchain(
     name = "default_osx_toolchain",
     target_compatible_with = [
-        "@bazel_tools//platforms:osx",
+        "@platforms//os:osx",
     ],
     toolchain = "@docker_config//:toolchain",
     toolchain_type = ":toolchain_type",