glsl: Remove ir_binop_greater and ir_binop_lequal expressions

NIR does not have these instructions.  TGSI and Mesa IR both implement
them using < and >=, repsectively.  Removing them deletes a bunch of
code and means I don't have to add code to the SPIR-V generator for
them.

v2: Rebase on 2+ years of change... and fix a major bug added in the
rebase.

   text	   data	    bss	    dec	    hex	filename
8255291	 268856	 294072	8818219	 868e2b	32-bit i965_dri.so before
8254235	 268856	 294072	8817163	 868a0b	32-bit i965_dri.so after
7815339	 345592	 420592	8581523	 82f193	64-bit i965_dri.so before
7813995	 345560	 420592	8580147	 82ec33	64-bit i965_dri.so after

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>

src/compiler/glsl/ir.cpp

@@ -487,10 +487,8 @@ ir_expression::ir_expression(int op, ir_rvalue *op0, ir_rvalue *op1)
 
    case ir_binop_equal:
    case ir_binop_nequal:
-   case ir_binop_lequal:
    case ir_binop_gequal:
    case ir_binop_less:
-   case ir_binop_greater:
       assert(op0->type == op1->type);
       this->type = glsl_type::get_instance(GLSL_TYPE_BOOL,
 					   op0->type->vector_elements, 1);