Tests: Disable trace compilation for MSVC and GCC New traces are hitting string literal limits with MSVC. Since we don't use MSVC or GCC for trace development or testing, this CL disables trace compilation for non-clang setups. Bug: b/181794064 Bug: angleproject:6009 Change-Id: I0377792a049153a5505ecda4346a3cec57c12e9e Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2922682 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Cody Northrop <cnorthrop@google.com>