[tracing] removed the second y-axis and added export of chart data #1027

Job	Run time
riscv-isa-sim	2m 12s
check-opcodes	6s
tc-gcc	1m 55s
tc-llvm	1m 56s
verilator	46s
verilator-model (minpool)	29s
verilator-model (mempool)	24s
build-apps-omp	1s
build-apps-gcc	1s
check-bootrom	1s
build-apps-llvm	1s
tc-halide	1s
build-apps-halide	1s
run-apps-halide	1s
run-apps-gcc	1s
run-apps-llvm	1s
unit-test	1s
clean-up-compile-runs (minpool)	2s
clean-up-compile-runs (mempool)	3s
clean-up	2s
	8m 5s

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