Refactor public key related performance test code #6085

Job	Run time
macOS (shared, xcode, macos-13)	7m 36s
macOS (amalgamation, xcode, macos-13)	7m 3s
Clang Tidy	1m 41s
Linux (gcc, shared)	2m 46s
Analysis (coverage, gcc, ubuntu-24.04)	26m 20s
macOS (shared, xcode, macos-14)	2m 43s
Linux (gcc, amalgamation)	4m 14s
Analysis (sanitizer, clang, ubuntu-24.04)	14m 29s
macOS (amalgamation, xcode, macos-14)	2m 49s
Linux (gcc, static)	1m 44s
Analysis (valgrind, clang, ubuntu-24.04)	29m 49s
Linux (clang, shared)	3m 3s
Analysis (fuzzers, gcc, ubuntu-24.04)	5m 33s
Special (examples, gcc, ubuntu-24.04)	1m 44s
Analysis (lint, gcc, ubuntu-24.04)	1m 8s
Windows (shared, x86_64, windows-2022)	8m 59s
Special (minimized, gcc, ubuntu-24.04)	21s
Analysis (format, gcc, ubuntu-24.04)	31s
Windows (static, x86_64, windows-2022)	5m 57s
Special (bsi, gcc, ubuntu-24.04)	1m 57s
Cross (cross-i386, gcc, ubuntu-22.04)	3m 22s
Analysis (limbo, gcc, ubuntu-24.04)	1m 42s
Windows (amalgamation, x86_64, windows-2022)	5m 17s
Special (docs, gcc, ubuntu-24.04)	58s
Cross (cross-arm32, gcc, ubuntu-24.04)	11m 26s
Windows (shared, x86, windows-2022)	10m 20s
Special (no_pcurves, gcc, ubuntu-24.04)	2m 1s
Cross (cross-arm64, gcc, ubuntu-24.04)	7m 36s
Cross (cross-ppc64, gcc, ubuntu-24.04)	7m 22s
Cross (cross-mips64, gcc, ubuntu-24.04)	8m 13s
Cross (cross-android-arm64, clang, ubuntu-24.04)	1m 34s
Cross (static, gcc, windows-2022, make)	2m 48s
Cross (cross-ios-arm64, xcode, macos-13)	59s
	3h 14m 5s

Provide feedback