GoogleTests are broken on macOS after upgrading to Boost 1.84.0

[str4d]

Describe the issue

See title.

Can you reliably reproduce the issue?

If so, please list the steps to reproduce below:

1. Upgrade Boost from 1.83.0 to 1.84.0
2. ./zcutil/build.sh on macOS
3. ./src/zcash-gtest

Expected behaviour

All tests pass (as they do on other platforms).

Actual behaviour + errors

Tests that use GoogleMock break like so:

 [ RUN      ] ChecktransactionTests.BadVersionTooLow
gtest/test_checktransaction.cpp:149: Failure
Actual function call count doesn't match EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-txns-version-too-low", false, ""))...
         Expected: to be called once
           Actual: never called - unsatisfied and active

--- Logs:
  ERROR rustzcash::transaction_ffi: Failed to parse transaction: Unknown transaction format
  ERROR main: CheckTransaction(): version too low
---
[  FAILED  ] ChecktransactionTests.BadVersionTooLow (0 ms)

The test is clearly doing the right thing (the log lines are from the correct error("...") calls). But the actual call to state.DoS(...) isn't being detected by the mock.

The weird thing is that GoogleTest does not depend on Boost, and there is no Boost code involved in the CValidationState API.

The version of Zcash you were using:

Latest master (as tested in #6798).