test: disable some tests on Linux portable ruby.

Library/Homebrew/test/cmd/install_spec.rb

@@ -6,7 +6,7 @@ describe "Homebrew.install_args" do
   it_behaves_like "parseable arguments"
 end
 
-describe "brew install", :integration_test do
+describe "brew install", :integration_test, :needs_no_bad_linux_portable_ruby do
   it "installs formulae" do
     setup_test_formula "testball1"
 

Library/Homebrew/test/cmd/migrate_spec.rb

@@ -6,7 +6,7 @@ describe "Homebrew.migrate_args" do
   it_behaves_like "parseable arguments"
 end
 
-describe "brew migrate", :integration_test do
+describe "brew migrate", :integration_test, :needs_no_bad_linux_portable_ruby do
   it "migrates a renamed Formula" do
     setup_test_formula "testball1"
     setup_test_formula "testball2"

Library/Homebrew/test/cmd/reinstall_spec.rb

@@ -7,7 +7,7 @@ describe "Homebrew.reinstall_args" do
   it_behaves_like "parseable arguments"
 end
 
-describe "brew reinstall", :integration_test do
+describe "brew reinstall", :integration_test, :needs_no_bad_linux_portable_ruby do
   it "reinstalls a Formula" do
     install_test_formula "testball"
     foo_dir = HOMEBREW_CELLAR/"testball/0.1/bin"

Library/Homebrew/test/cmd/upgrade_spec.rb

@@ -6,7 +6,7 @@ describe "Homebrew.upgrade_args" do
   it_behaves_like "parseable arguments"
 end
 
-describe "brew upgrade", :integration_test do
+describe "brew upgrade", :integration_test, :needs_no_bad_linux_portable_ruby do
   it "upgrades a Formula and cleans up old versions" do
     setup_test_formula "testball"
     (HOMEBREW_CELLAR/"testball/0.0.1/foo").mkpath

Library/Homebrew/test/dev-cmd/ruby_spec.rb

@@ -6,7 +6,7 @@ describe "Homebrew.ruby_args" do
   it_behaves_like "parseable arguments"
 end
 
-describe "brew ruby", :integration_test do
+describe "brew ruby", :integration_test, :needs_no_bad_linux_portable_ruby do
   it "executes ruby code with Homebrew's libraries loaded" do
     expect { brew "ruby", "-e", "exit 0" }
       .to be_a_success

Library/Homebrew/test/dev-cmd/test_spec.rb

@@ -6,7 +6,7 @@ describe "Homebrew.test_args" do
   it_behaves_like "parseable arguments"
 end
 
-describe "brew test", :integration_test do
+describe "brew test", :integration_test, :needs_no_bad_linux_portable_ruby do
   it "tests a given Formula" do
     install_test_formula "testball", <<~'RUBY'
       test do

Library/Homebrew/test/spec_helper.rb

@@ -132,6 +132,10 @@ RSpec.configure do |config|
     skip "unzip not installed." unless which("unzip")
   end
 
+  config.before(:each, :needs_no_bad_linux_portable_ruby) do
+    skip "using Linux portable-ruby." if OS.linux? && RUBY_PATH.to_s.end_with?("portable-ruby/2.6.3/bin/ruby")
+  end
+
   config.around do |example|
     def find_files
       Find.find(TEST_TMPDIR)