Only set global debug level from settings if above 0 #2845

Job	Run time
codegen	12s
linux-32-no-asm	2m 14s
linux-32 (Debug)	1m 55s
chromium	1m 22s
linux-32 (Release)	2m 2s
linux (gcc, g++, Debug, ubuntu-20.04)	2m 41s
linux-no-asm	3m 13s
linux (gcc, g++, Debug, ubuntu-22.04)	2m 57s
linux (gcc, g++, Release, ubuntu-20.04)	7m 2s
linux (gcc, g++, Release, ubuntu-22.04)	6m 56s
linux (clang, clang++, Debug, ubuntu-20.04)	1m 59s
linux (clang, clang++, Debug, ubuntu-22.04)	2m 53s
linux (clang, clang++, Release, ubuntu-20.04)	4m 18s
linux (clang, clang++, Release, ubuntu-22.04)	4m 41s
mingw	1m 24s
windows_vs-no-asm (Win32)	4m 24s
windows_clang (clang, Debug)	4m 15s
windows_vs-no-asm (x64)	4m 57s
windows_clang (clang, Release)	3m 32s
mingw-no-asm	1m 11s
mingw-no-asm-explicit	1m 21s
windows_clang (clang-cl, Debug)	3m 35s
mingw-use-gas	1m 10s
windows_vs (Win32, Debug)	5m 27s
windows_clang (clang-cl, Release)	4m 43s
windows_vs (Win32, Release)	4m 15s
windows_vs (x64, Debug)	5m 23s
windows_vs (x64, Release)	3m 42s
mac (Debug, APPLE_STATIC_LOADER=ON)	4m 55s
mac (Debug, APPLE_STATIC_LOADER=OFF)	6m 50s
iOS	53s
mac (Release, APPLE_STATIC_LOADER=ON)	5m 45s
Universal Binary Testing (STATIC ON) w/ Ninja	1m 50s
tvOS	52s
Universal Binary Testing (STATIC ON) w/ Xcode	4m 20s
mac (Release, APPLE_STATIC_LOADER=OFF)	5m 59s
Universal Binary Testing (STATIC OFF) w/ Ninja	2m 3s
Universal Binary Testing (STATIC OFF) w/ Xcode	4m 38s
	2h 11m 49s

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