Fix garbled test output

[zvecr]

Description

Currently some tests output as,

Testing secure
Running 10 tests from 1 test suite.
[==========] [----------] Global test environment set-up.
10 tests from Secure[----------] 
Secure.test_lock[ RUN      ] 
Secure.test_lock (0 ms)
[       OK ] Secure.test_unlock_timeout[ RUN      ] 
Secure.test_unlock_timeout (0 ms)
[       OK ] Secure.test_unlock_request[ RUN      ] 
Secure.test_unlock_request (0 ms)
[       OK ] Secure.test_unlock_request_fail[ RUN      ] 
Secure.test_unlock_request_fail (0 ms)
[       OK ] Secure.test_unlock_request_timeout[ RUN      ] 
Secure.test_unlock_request_timeout (0 ms)
[       OK ] Secure.test_unlock_request_fail_mid[ RUN      ] 
Secure.test_unlock_request_fail_mid (0 ms)
[       OK ] Secure.test_unlock_request_fail_out_of_order[ RUN      ] 
Secure.test_unlock_request_fail_out_of_order (0 ms)
[       OK ] Secure.test_unlock_request_on_layer[ RUN      ] 
Secure.test_unlock_request_on_layer (0 ms)
[       OK ] Secure.test_unlock_request_mid_stroke[ RUN      ] 
Secure.test_unlock_request_mid_stroke (0 ms)
[       OK ] Secure.test_unlock_request_mods[ RUN      ] 
Secure.test_unlock_request_mods (0 ms)
[       OK ] 10 tests from Secure (3 ms total)

[----------] [----------] Global test environment tear-down
10 tests from 1 test suite ran. (3 ms total)[==========] 
10 tests.
[  PASSED  ] 

Issue is due to a mixture of stdout/stderr and gtest flushing stdout.

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout/userspace (addition or update)
• Documentation

Issues Fixed or Closed by This PR

Checklist

• My code follows the code style of this project: C, Python
• I have read the PR Checklist document and have made the appropriate changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).