Load toolchains_llvm dependencies earlier in tests (#682)

There are certain dependency requirements for toolchains_llvm. Without
Bzlmod, the user must take care that are correct or call the macro to
load transitive dependencies.
If this is done in a too late step, a version of a transitive dependency
might be taken instead of the one that toolchains_llvm require.
This commit move the load at the beginning to mimic what the user should
do without Bzlmod.
With this change, the version of skylib defined in toolchains_llvm is
taken instead of the one defined in bazel_features repository.

Author: limdor

tests/WORKSPACE

@@ -19,6 +19,10 @@ local_repository(
     path = "..",
 )
 
+load("@toolchains_llvm//toolchain:deps.bzl", "bazel_toolchain_dependencies")
+
+bazel_toolchain_dependencies()
+
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 
 http_archive(
@@ -50,10 +54,6 @@ load("@tar.bzl//tar:extensions.bzl", "create_repositories")
 
 create_repositories()
 
-load("@toolchains_llvm//toolchain:deps.bzl", "bazel_toolchain_dependencies")
-
-bazel_toolchain_dependencies()
-
 load("@toolchains_llvm//toolchain:rules.bzl", "llvm_toolchain")
 
 # When updating this version, also update the versions associated with