[CI] Do not enable debug for TSAN builds

Summary:
Having debug enabled for TSAN builds is problematic since DEBUG_LOCKORDER is enabled,
which may conflict with TSAN's own deadlock checks. While we could disable only DEBUG_LOCKORDER,
doing this is cleaner (compare to something like D6540) and enabling debug is not required for
informative TSAN output, since -g is set either way (-g provides line numbers and file names
in failure logs).

Test Plan:
Run TSAN on this diff. It still may fail due to an unrelated, outstanding issue.
https://build.bitcoinabc.org/viewLog.html?buildId=76914&buildTypeId=BitcoinABC_BitcoinAbcStaging&tab=buildLog

Reviewers: #bitcoin_abc, deadalnix

Reviewed By: #bitcoin_abc, deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D6541