[et] compile errors are not relative to CWD #157735
Description
This completely jacks up VSCode so you can no longer click on errors and have them link to the source of the problem.
steps to reproduce
./flutter/bin/et build -c host_debug_unopt_arm64
observed results
../../flutter/impeller/renderer/testing/mocks.h:50:15: error: virtual function 'OnCreateBuffer' has a different return type ('typename ::testing::internal::Function< ::testing::internal::identity_t<std::shared_ptr<DeviceBuffer>> (const DeviceBufferDescriptor &)>::Result' (aka 'std::shared_ptr<impeller::DeviceBuffer>')) than the function it overrides (which has return type 'std::unique_ptr<DeviceBuffer>')
49 | MOCK_METHOD(std::shared_ptr<DeviceBuffer>,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
50 | OnCreateBuffer,
| ^~~~~~~~~~~~~~~
51 | (const DeviceBufferDescriptor& desc),
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
52 | (override));
| ~~~~~~~~~~~
expected results
./flutter/impeller/renderer/testing/mocks.h:50:15: error: virtual function 'OnCreateBuffer' has a different return type ('typename ::testing::internal::Function< ::testing::internal::identity_t<std::shared_ptr<DeviceBuffer>> (const DeviceBufferDescriptor &)>::Result' (aka 'std::shared_ptr<impeller::DeviceBuffer>')) than the function it overrides (which has return type 'std::unique_ptr<DeviceBuffer>')
49 | MOCK_METHOD(std::shared_ptr<DeviceBuffer>,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
50 | OnCreateBuffer,
| ^~~~~~~~~~~~~~~
51 | (const DeviceBufferDescriptor& desc),
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
52 | (override));
| ~~~~~~~~~~~