[iOS] Simplify iOS performance measurement scripts

[matouskozak]

• Refactor naming to be consistent
• Remove StripSymbol=false measurements

Associated dotnet/runtime PR: dotnet/runtime#120531
Test run: https://dev.azure.com/dnceng/internal/_build/results?buildId=2810833

[Copilot]

Pull Request Overview

This PR simplifies iOS performance measurement scripts by refactoring naming conventions to be more consistent and removing measurements where symbol stripping is disabled (StripSymbol=false scenarios).

• Standardized artifact naming to include runtime type, code generation method, and symbol stripping status
• Removed all performance measurement scenarios that keep symbols (StripSymbols=false)
• Changed default iOSStripSymbols parameter from false to true

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
eng/pipelines/upload-build-artifacts-jobs.yml	Updated artifact names to include runtime type prefixes and removed symbol-keeping variants
eng/pipelines/templates/runtime-perf-job.yml	Simplified conditional logic by removing StripSymbols=false scenarios and updated artifact names
eng/pipelines/templates/run-performance-job.yml	Changed default iOSStripSymbols parameter from false to true
eng/pipelines/runtime-ios-scenarios-perf-jobs.yml	Removed duplicate job configurations for StripSymbols=false scenarios and updated remaining jobs

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