[Benchmark X64] [MihaZupan] Delete AVX512 paths from `IndexOf(string)`

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Job completed in 19 minutes 48 seconds (remote runner delay: 1 minute 29 seconds).

Using arguments: benchmark Perf_Regex_Industry_SliceSlice https://github.com/MihaZupan/performance/tree/compiled-regex-only -medium -dependsOn 117887 -NoPRLink

System.Text.RegularExpressions.Tests.Perf_Regex_Industry_SliceSlice

BenchmarkDotNet v0.14.1-nightly.20250107.205, Linux Ubuntu 22.04.5 LTS (Jammy Jellyfish)
AMD EPYC 9V74, 1 CPU, 8 logical and 4 physical cores
MediumRun : .NET 10.0.0 (42.42.42.42424), X64 RyuJIT AVX-512F+CD+BW+DQ+VL+VBMI
Job=MediumRun  OutlierMode=Default  IterationCount=15
LaunchCount=2  MemoryRandomization=Default  MinIterationCount=3
WarmupCount=10

Method	Toolchain	Options	Mean	Error	Ratio	Allocated	Alloc Ratio
Count	Main	Compiled	374.6 ms	1.53 ms	1.00	736 B	1.00
Count	PR	Compiled	263.6 ms	0.88 ms	0.70	200 B	0.27
Count	Main	IgnoreCase, Compiled	429.2 ms	0.99 ms	1.00	1072 B	1.00
Count	PR	IgnoreCase, Compiled	306.6 ms	1.65 ms	0.71	536 B	0.50

Artifacts:

• BDN_Artifacts.zip (16 KB)
• results.md (1 KB)

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