Tests

Bump third_party/pigweed/repo from `1f12d06` to `a551daa` #2025

Job	Run time
REPL Tests - Darwin	0s
REPL Tests - Linux	1m 37s
Test Suites - Darwin (no-ble-asan-clang)	3m 15s
Test Suites - Linux (no-ble-tsan-clang)	1m 48s
Test Suites - Darwin (no-ble-tsan-clang)	2m 32s
	9m 12s

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