test: mark hr-time WPT flaky on macos15-x64 #8401

Job	Run time
Build slim tarball	1m 30s
aarch64-linux: Cache V8 build	22s
x86_64-linux: with shared libraries	27m 31s
x86_64-darwin: with shared libraries	39m 59s
aarch64-darwin: with shared libraries	26m 50s
aarch64-linux: with shared boringssl-0.20260526.0	23m 8s
aarch64-linux: with shared openssl-3.0.21	24m 30s
aarch64-linux: with shared openssl-4.0.1	22m 57s
aarch64-linux: with shared openssl-3.5.7	23m 27s
aarch64-linux: with shared openssl-3.6.2	24m 32s
aarch64-linux: with shared openssl-1.1.1w	23m 45s
	3h 58m 31s

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