[rubygems/rubygems] Remove unnecessary branching

We now run specs against a single version, so I prefer to keep a single
branch. Once we bump the major version, this will need very little
updates, and that seems fine.

ruby/rubygems@3866d25a00

Author: deivid-rodriguez

spec/bundler/commands/clean_spec.rb

@@ -151,7 +151,7 @@ def should_not_have_gems(*gems)
     bundle :clean
 
     digest = Digest(:SHA1).hexdigest(git_path.to_s)
-    cache_path = Bundler.feature_flag.global_gem_cache? ? home(".bundle/cache/git/foo-1.0-#{digest}") : vendored_gems("cache/bundler/git/foo-1.0-#{digest}")
+    cache_path = vendored_gems("cache/bundler/git/foo-1.0-#{digest}")
     expect(cache_path).to exist
   end
 

spec/bundler/install/gems/compact_index_spec.rb

@@ -1010,11 +1010,7 @@ def start
         gem "myrack"
       G
 
-      gem_path = if Bundler.feature_flag.global_gem_cache?
-        default_cache_path.dirname.join("cache", "gems", "localgemserver.test.80.dd34752a738ee965a2a4298dc16db6c5", "myrack-1.0.0.gem")
-      else
-        default_cache_path.dirname.join("myrack-1.0.0.gem")
-      end
+      gem_path = default_cache_path.dirname.join("myrack-1.0.0.gem")
 
       expect(exitstatus).to eq(37)
       expect(err).to eq <<~E.strip

spec/bundler/support/path.rb

@@ -136,19 +136,11 @@ def home(*path)
     end
 
     def default_bundle_path(*path)
-      if Bundler.feature_flag.bundler_4_mode?
-        local_gem_path(*path)
-      else
-        system_gem_path(*path)
-      end
+      system_gem_path(*path)
     end
 
     def default_cache_path(*path)
-      if Bundler.feature_flag.global_gem_cache?
-        home(".bundle/cache", *path)
-      else
-        default_bundle_path("cache/bundler", *path)
-      end
+      default_bundle_path("cache/bundler", *path)
     end
 
     def compact_index_cache_path