glsl2: Fix expected type for multiplying vector with non-square matrix.

glsl2: Fix expected type for multiplying vector with non-square matrix.

Previously, the compiler expected the result of the multiplication to
be of the same type as the vector. This is correct for square
matrices, but wrong for all others.

We fix this by instead expecting a vector with the same number of rows
as the matrix (for the case of M*v with a column vector) or the same
number of columns as the matrix (for v*M with a row vector).

This fix causes the following four glean tests to now pass:

	glsl1-mat4x2 * vec4
  	glsl1-vec2 * mat4x2 multiply
  	glsl1-vec3 * mat4x3 multiply
  	glsl1-vec4 * mat3x4 multiply