Update toolchain to nightly 2023-08-04 #5098

Job	Run time
bookrunner	29m 36s
releasebundle-macos (macos-11)	9m 30s
perf	38m 44s
regression (macos-11)	33m 27s
regression (ubuntu-20.04)	35m 49s
regression (ubuntu-22.04)	33m 45s
benchcomp-tests	5m 34s
write-json-symtab-regression	25m 29s
releasebundle-ubuntu	35m 21s
	4h 7m 15s

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