[VL] Fix wrong warning of "Memory overhead is set to ..." under default Spark config settings

[zhztheplayer]

This is a minor fix for warning "Memory overhead is set to ..." that is sometimes unexpectedly appearing, which is because of the incorrect precision of the overhead vs desired overhead comparison.

[GlutenPerfBot]

===== Performance report for TPCH SF2000 with Velox backend, for reference only ====

query	log/native_master_01_08_2025_time.csv	log/native_master_12_07_2024_36f92a5294_time.csv	difference	percentage
q1	44.05	52.51	8.457	119.20%
q2	43.68	38.81	-4.869	88.85%
q3	90.86	83.81	-7.049	92.24%
q4	69.92	64.32	-5.604	91.98%
q5	179.15	153.39	-25.756	85.62%
q6	20.77	19.21	-1.560	92.49%
q7	104.25	179.25	75.001	171.94%
q8	185.41	162.48	-22.929	87.63%
q9	283.27	249.00	-34.268	87.90%
q10	102.84	90.65	-12.192	88.15%
q11	34.40	37.49	3.086	108.97%
q12	43.58	41.29	-2.290	94.75%
q13	76.49	77.55	1.061	101.39%
q14	36.05	34.93	-1.126	96.88%
q15	66.46	59.03	-7.432	88.82%
q16	27.78	23.33	-4.455	83.96%
q17	234.35	223.58	-10.770	95.40%
q18	357.76	354.87	-2.889	99.19%
q19	36.28	35.00	-1.280	96.47%
q20	61.00	58.09	-2.913	95.22%
q21	536.80	1056.98	520.180	196.90%
q22	24.33	36.85	12.521	151.47%
total	2659.47	3132.39	472.924	117.78%