Bundler performance optimizations: 2x faster installs #13543

Job	Run time
Handling issues with a shared gem home (system)	15s
Handling issues with a shared gem home (dev)	20s
Handling gems shipped by default with RVM (3.2, 3.2.9)	9s
Install Rubygems on Windows (3.3)	1m 45s
Install Rubygems on Windows (3.2)	1m 33s
Handling gems shipped by default with RVM (3.3, 3.3.9)	11s
Handling gems shipped by default with RVM (3.4, 3.4.5)	9s
Install Rubygems on Windows (3.4)	1m 32s
Install Rubygems on Windows (jruby)	3m 4s
Install Rubygems on Ubuntu (3.3, openssl)	2m 32s
Install Rubygems on Ubuntu (3.3, no-openssl)	2m 22s
Install Rubygems on Ubuntu (jruby, no-openssl)	3m 9s
Install Rubygems on Ubuntu (3.4, no-openssl)	2m 16s
Install Rubygems on Ubuntu (3.2, no-openssl)	2m 11s
Install Rubygems on Ubuntu (3.4, openssl)	2m 30s
Install Rubygems on Ubuntu (3.2, openssl)	2m 26s
Install Rubygems on Ubuntu (truffleruby, openssl)	3m 25s
Install Rubygems on Ubuntu (jruby, openssl)	3m 29s
Install Rubygems on Ubuntu (truffleruby, no-openssl)	2m 55s
All install-rubygems jobs pass	3s
	36m 16s

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