[RF] Fixes and performance improvements for `RooAbsArg::getParameters()` #22856

Job	Run time
Upload Event Payload	3s
mac-beta ARM64 CMAKE_CXX_STANDARD=23	1s
mac15 ARM64 CMAKE_CXX_STANDARD=23	8m 9s
mac13 ARM64 builtin_zlib=ON	8m 9s
Windows 10 x86 Release	7m 57s
Windows 10 x64 Release	1s
mac14 X64 CMAKE_CXX_STANDARD=20	1s
alma9 march_native CMAKE_BUILD_TYPE=RelWithDebInfo, CMAKE_CXX_FLAGS=-march=native, CMAKE_C_FLAGS=-march=native, builtin_zlib=ON, builtin_zstd=ON	8m 7s
alma10	8m 7s
fedora42 CMAKE_CXX_STANDARD=23	8m 11s
alma9 CMAKE_BUILD_TYPE=Debug	8m 10s
alma8	8m 11s
alma9 modules_off runtime_cxxmodules=Off	8m 13s
ubuntu2504 CMAKE_CXX_STANDARD=23	8m 11s
debian125 CMAKE_CXX_STANDARD=20, dev=ON, CMAKE_CXX_FLAGS=-Wsuggest-override	8m 7s
alma9 arm64 CMAKE_BUILD_TYPE=RelWithDebInfo, builtin_zlib=ON, builtin_zstd=ON	8m 10s
ubuntu22 imt=Off, CMAKE_BUILD_TYPE=Debug	8m 9s
ubuntu2404 CMAKE_BUILD_TYPE=Debug	8m 10s
alma10 clang Ninja CMAKE_C_COMPILER=clang, CMAKE_CXX_COMPILER=clang++	8m 7s
ubuntu2510 CMAKE_CXX_STANDARD=23	8m 11s
rawhide Fedora pydebug CMAKE_CXX_STANDARD=23	8m 10s
fedora43 CMAKE_CXX_STANDARD=23	8m 10s
	2h 26m 45s

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