MSVC 2017 debug build fails to compile SPIRV-Tools test/opt/fold_test.cpp: requires /bigobj flag

[dneto0]

Found this in the MSVC 2017 debug build run for #1339

https://source.cloud.google.com/results/invocations/bb339ff7-222e-444f-add4-1c2ea0dea427/targets/graphics_shader_compiler%2Fshaderc%2Fwindows%2Fpresubmit_debug_2017/log

[270/637] Building CXX object third_party\spirv-tools\test\opt\CMakeFiles\test_opt.dir\fold_test.cpp.obj
FAILED: third_party/spirv-tools/test/opt/CMakeFiles/test_opt.dir/fold_test.cpp.obj
C:\PROGRA2\MIB0551\2017\COMMUN1\VC\Tools\MSVC\14161.270\bin\Hostx64\x64\cl.exe /nologo /TP -DSPIRV_COLOR_TERMINAL -DSPIRV_WINDOWS -IT:\src\github\shaderc\third_party\spirv-tools -IT:\src\github\shaderc\third_party\spirv-headers\include -IT:\src\github\shaderc\third_party\spirv-tools\include -IT:\src\github\shaderc\third_party\spirv-tools\test -IT:\src\github\shaderc\build\third_party\spirv-tools -IT:\src\github\shaderc\third_party\effcee -IT:\src\github\shaderc\third_party\effcee\effcee.. -IT:\src\github\shaderc\third_party\re2 -IT:\src\github\shaderc\third_party\googletest\googletest\include -IT:\src\github\shaderc\third_party\googletest\googlemock\include -IT:\src\github\shaderc\third_party\googletest\googlemock -IT:\src\github\shaderc\third_party\googletest\googletest /DWIN32 /D_WINDOWS /GR /EHsc /Zi /Ob0 /Od /RTC1 -MTd -w -DSPIRV_CHECK_CONTEXT -D_CRT_SECURE_NO_WARNINGS -D_SCL_SECURE_NO_WARNINGS /wd4800 /wd4819 /WX /EHs /wd4503 /DGTEST_HAS_COMBINE=1 -std:c++17 /showIncludes /Fothird_party\spirv-tools\test\opt\CMakeFiles\test_opt.dir\fold_test.cpp.obj /Fdthird_party\spirv-tools\test\opt\CMakeFiles\test_opt.dir\ /FS -c T:\src\github\shaderc\third_party\spirv-tools\test\opt\fold_test.cpp
T:\src\github\shaderc\third_party\spirv-tools\test\opt\fold_test.cpp : fatal error C1128: number of sections exceeded object file format limit: compile with /bigobj

[dneto0]

Also filed as KhronosGroup/SPIRV-Tools#5335