Build libxml2 for LLDB #1125

Job	Run time
Build only sysroot - exceptions	17m 27s
Build x86_64-macos	6m 31s
Build x86_64-linux	26m 27s
Build arm64-macos	18m 6s
Build arm64-linux	17m 51s
Build only sysroot - default	17m 4s
Build arm64-windows	1h 52m 30s
Build x86_64-windows	47m 22s
Test standalone toolchain	4m 35s
Finalize wasi-sdk artifacts	13m 6s
Build only sysroot - default	17m 4s
Build arm64-linux	17m 51s
Test standalone toolchain	4m 0s
Build x86_64-linux	26m 27s
Build only sysroot - exceptions	17m 27s
Finalize wasi-sdk artifacts	13m 6s
Build x86_64-macos	6m 31s
Build arm64-macos	18m 6s
Build x86_64-windows	47m 22s
Build arm64-windows	1h 52m 30s
	9h 21m 23s

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