tests: Add --valgrind option to test/fuzz/test_runner.py for running fuzzing test cases under valgrind

Summary:

Add --valgrind option to test/fuzz/test_runner.py for running fuzzing
test cases under valgrind.

Backport of core PR18159.

Test Plan:

ninja bitcoin-fuzzers
./test/fuzz/test_runner.py --vagrind <path_to_corpus>

Reviewers: #bitcoin_abc, PiRK

Reviewed By: PiRK

Differential Revision: https://reviews.bitcoinabc.org/D8221