Added tests which check component aliasing between types that have
different bit widths.

From Section 4.4.1 (Input Layout Qualifiers) of the GLSL 4.60 spec:

    "Further, when location aliasing, the aliases sharing the location
     must have the same underlying numerical type and bit
     width (floating-point or integer, 32-bit versus 64-bit, etc.)
     and the same auxiliary storage and interpolation
     qualification. The one exception where component aliasing is
     permitted is for two input variables (not block members) to a
     vertex shader, which are allowed to have component aliasing. This
     vertex-variable component aliasing is intended only to support
     vertex shaders where each execution path accesses at most one
     input per each aliased component. Implementations are permitted,
     but not required, to generate link-time errors if they detect
     that every path through the vertex shader executable accesses
     multiple inputs aliased to any single component."

Cc: Timothy Arceri <tarceri@itsqueeze.com>
Cc: Iago Toral Quiroga <itoral@igalia.com>
Cc: Ilia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: Andres Gomez <agomez@igalia.com>
Reviewed-by: Juan A. Suarez <jasuarez@igalia.com>