`install_python()`: support building optimized Python #1026

Job	Run time
OS=macOS-latest R=release py=3.9	7m 26s
OS=windows-latest R=release py=3.9	22m 54s
OS=ubuntu-latest R=release py=3.9	4m 50s
OS=ubuntu-latest R=oldrel-1 py=3.9	4m 47s
OS=ubuntu-latest R=oldrel-2 py=3.9	4m 23s
OS=ubuntu-20.04 R=oldrel-3 py=3.8	4m 16s
OS=ubuntu-20.04 R=oldrel-4 py=3.8	4m 13s
OS=ubuntu-latest R=release py=3.7	5m 41s
OS=ubuntu-latest R=release py=3.8	4m 47s
OS=ubuntu-latest R=release py=3.10	5m 12s
OS=ubuntu-latest R=release py=3.11	4m 39s
OS=ubuntu-latest R=release py=3.12	5m 18s
OS=ubuntu-latest R=devel py=3.12	4m 24s
	1h 22m 50s

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