This change causes ES shaders to precision qualifiers for build-in functions as defined in ESSL spec. It especially mattersfor functions that are defined as highp or taking a highp.

Fixes vulkanCTS dEQP-VK.glsl.builtin.function.integer.bitfieldreverse.*, where bitfieldReverse() retval was wrongly marked as RelaxedPrecision.

Note: floatBitsToInt/floatBitsToUInt precision is also broken, but in different way - so it is not addressed here.