Avoid invalid hit kinds with OpReportIntersection

Avoid invalid hit kinds with OpReportIntersection

OpReportIntersectionKHR accepts values in the [0, 127] range for the hit kind,
while gl_HitKindFrontFacingTriangleEXT or gl_HitKindBackFacingTriangleEXT are
reserved values outside that range and should not be used with
reportIntersectionEXT() in GLSL.

Affected tests:
dEQP-VK.ray_tracing_pipeline.builtin.*
dEQP-VK.ray_tracing_pipeline.memguarantee.*
dEQP-VK.ray_tracing_pipeline.complexcontrolflow.*

Components: Vulkan
VK-GL-CTS issue: 2626

Change-Id: Ic69abbb53968036ab56ebad4a832485fbccd8fb5