glsl: Fix implicit conversions in non-constructor function calls

glsl: Fix implicit conversions in non-constructor function calls

Context
-------
In ast_function_expression::hir(), parameter_lists_match() checks if the
function call's actual parameter list matches the signature's parameter
list, where the match may require implicit conversion of some arguments.
To check if an implicit conversion exists between individual arguments,
type_compare() is used.

Problems
--------
type_compare() allowed the following illegal implicit conversions:
    bool -> float
    bvecN -> vecN

    int -> uint
    ivecN -> uvecN

    uint -> int
    uvecN -> ivecN

Change
------
type_compare() is buggy, so replace it with glsl_type::can_be_implicitly_converted_to().
This comprises a rewrite of parameter_lists_match().

Fixes piglit:spec/glsl-1.20/compiler/built-in-functions/outerProduct-bvec*.vert

Note: This is a candidate for the 7.10 and 7.11 branches.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Chad Versace <chad@chad-versace.us>