GCC 11 build fixes for opengl-es-cts

GCC 11 build fixes for opengl-es-cts

Add missing limits header to misc files to fix compilation.

+ changes to fix following compilation warnings:

"warning: expression does not compute the number of elements in this array;
element type is ‘std::string’ {aka ‘std::__cxx11::basic_string<char>’},
not ‘std::string [15]’ {aka ‘std::__cxx11::basic_string<char> [15]’}
[-Wsizeof-array-div]"

"warning: loop variable ‘ext’ creates a copy from type
‘const std::__cxx11::basic_string<char>’ [-Wrange-loop-construct]"

"warning: comparison of unsigned expression in ‘>= 0’ is always true
[-Wtype-limits]"

Components: OpenGL ES
VK-GL-CTS issue: 3245

Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Change-Id: If62a44d47afccf1118a6fb0986d0c6e715f78c48