Update abseil to the latest LTS. #615

Job	Run time
C++ Lint	6m 20s
Windows MSVC 17 x64 - C++ Benchmark	6m 24s
ubuntu-20.04 - C++ Benchmark	1m 57s
Windows MSVC 17 x64 - test run	30m 52s
ubuntu-20.04 - test run	18m 56s
Windows MSVC 17 x86 - test run	31m 55s
Windows MSVC 16 x64 - test run	28m 41s
macos-12 - C++ Benchmark	2m 54s
macos-12 - test run	29m 50s
ubuntu-20.04 - with Clang compiler - test run	20m 10s
ubuntu-20.04 - without libclang completer - test run	18m 55s
	3h 16m 54s

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