Simplify namespace of mathTest #4644

Job	Run time
clang-format	17s
linux_clang-14_cuda-11.2_debug_analysis	13m 20s
windows_cl-2022_debug_analysis	15m 47s
macos_xcode-14.2_debug_analysis	23m 46s
linux_gcc-12_debug_analysis	13m 29s
macos_xcode-13.2.1_debug	15m 0s
macos_xcode-14.2_release	22m 23s
macos_xcode-14.3.1_debug	19m 36s
windows_cl-2022_release	17m 55s
windows_cl-2022_debug	12m 55s
linux_gcc-9_debug	13m 49s
linux_gcc-12_release_c++20	12m 36s
linux_gcc-13_debug	10m 59s
linux_clang-10_release	9m 14s
linux_clang-12_release	29m 13s
linux_clang-13_debug	7m 2s
linux_clang-16_debug_ubsan	9m 57s
linux_clang-16_debug_tsan	11m 31s
	4h 18m 49s

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