Bump third_party/pigweed/repo from `9504c03` to `8b5d45a` #1127

Job	Run time
REPL Tests - Linux	2m 36s
Test Suites - Linux (no-ble-tsan-clang)	2m 51s
Test Suites - Darwin (no-ble-asan-clang)	3m 26s
Test Suites - Darwin (no-ble-tsan-clang)	1s
REPL Tests - Darwin	0s
	8m 54s

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