[Tests] Move add_multi and synthesis tests to benchmarking branch

Remove test scripts and templates that are redundant with pytest coverage:
- run_add_multi_comp_tests.sh + add_multi_comp_tb_template.sv/.tcl
- run_mvu_add_multi_comp_tests.sh + mvu_add_multi_comp_tb_template.sv/.tcl
- run_mvu_comp_synth_tests.sh + mvu_comp_synth_tb_template.tcl

These remain available in the compressor-benchmarking branch for
detailed performance analysis. Core validation covered by:
- run_tests.sh (compressor unit tests)
- run_dotp_comp_tests.sh (dotp_comp integration)
- run_mvu_comp_tests.sh (full MVU integration)
- pytest test_fpgadataflow_rtl_mvau (FINN node tests)

Author: sgerber-amd