[rubygems/rubygems] Normalize setting `GEM_PATH`

https://github.com/rubygems/rubygems/commit/4188ebd568

lib/bundler.rb

@@ -661,12 +661,12 @@ EOF
       configure_gem_home
     end
 
-    def configure_gem_path(env = ENV)
+    def configure_gem_path
       unless use_system_gems?
         # this needs to be empty string to cause
         # PathSupport.split_gem_path to only load up the
         # Bundler --path setting as the GEM_PATH.
-        env["GEM_PATH"] = ""
+        Bundler::SharedHelpers.set_env "GEM_PATH", ""
       end
     end
 

spec/bundler/bundler/bundler_spec.rb

@@ -176,11 +176,9 @@ RSpec.describe Bundler do
   describe "configuration" do
     context "disable_shared_gems" do
       it "should unset GEM_PATH with empty string" do
-        env = {}
         expect(Bundler).to receive(:use_system_gems?).and_return(false)
-        Bundler.send(:configure_gem_path, env)
-        expect(env.keys).to include("GEM_PATH")
-        expect(env["GEM_PATH"]).to eq ""
+        Bundler.send(:configure_gem_path)
+        expect(ENV["GEM_PATH"]).to eq ""
       end
     end
   end