draw: correctly handle max_index=0xffffffff case in vcache code
draw: correctly handle max_index=0xffffffff case in vcache code

If max_index=0xffffffff and elt_bias > 0 the test for
elt_bias + max_index >= DRAW_PIPE_MAX_VERTICES
was wrong.  Check earlier if max_index=0xffffffff and do the
"fail" case.

This fixes the piglit draw-elements-base-vertex test (and probably
some other things).

KTXSoftware/glsl2agal,zeux/glsl-optimizer,wolf96/glsl-optimizer,mcanthony/glsl-optimizer,dellis1972/glsl-optimizer,zeux/glsl-optimizer,bkaradzic/glsl-optimizer,mapbox/glsl-optimizer,dellis1972/glsl-optimizer,metora/MesaGLSLCompiler,mapbox/glsl-optimizer,djreep81/glsl-optimizer,tokyovigilante/glsl-optimizer,tokyovigilante/glsl-optimizer,bkaradzic/glsl-optimizer,djreep81/glsl-optimizer,benaadams/glsl-optimizer,mapbox/glsl-optimizer,adobe/glsl2agal,metora/MesaGLSLCompiler,KTXSoftware/glsl2agal,metora/MesaGLSLCompiler,tokyovigilante/glsl-optimizer,jbarczak/glsl-optimizer,djreep81/glsl-optimizer,benaadams/glsl-optimizer,adobe/glsl2agal,zeux/glsl-optimizer,mapbox/glsl-optimizer,dellis1972/glsl-optimizer,benaadams/glsl-optimizer,KTXSoftware/glsl2agal,tokyovigilante/glsl-optimizer,zz85/glsl-optimizer,jbarczak/glsl-optimizer,mcanthony/glsl-optimizer,zeux/glsl-optimizer,mcanthony/glsl-optimizer,KTXSoftware/glsl2agal,zz85/glsl-optimizer,wolf96/glsl-optimizer,zz85/glsl-optimizer,tokyovigilante/glsl-optimizer,mcanthony/glsl-optimizer,adobe/glsl2agal,zz85/glsl-optimizer,dellis1972/glsl-optimizer,bkaradzic/glsl-optimizer,adobe/glsl2agal,jbarczak/glsl-optimizer,benaadams/glsl-optimizer,benaadams/glsl-optimizer,adobe/glsl2agal,KTXSoftware/glsl2agal,mcanthony/glsl-optimizer,dellis1972/glsl-optimizer,bkaradzic/glsl-optimizer,jbarczak/glsl-optimizer,zeux/glsl-optimizer,jbarczak/glsl-optimizer,djreep81/glsl-optimizer,bkaradzic/glsl-optimizer,wolf96/glsl-optimizer,wolf96/glsl-optimizer,benaadams/glsl-optimizer,wolf96/glsl-optimizer,zz85/glsl-optimizer,mapbox/glsl-optimizer,djreep81/glsl-optimizer,zz85/glsl-optimizer