D3D compiler can't resolve between these overloaded functions:

float4 vec4(float2x2 x0);
float4 vec4(float4 x0);

Include the parameter types in the function name to disambiguate
between overloaded user-defined functions and constructors, like this:

float4 vec4_float2x2(float2x2 x0);
float4 vec4_float4(float4 x0);

This is only done for float2x2 and float4 parameters, other parameter
types like float2x3 vs. float3x2 don't need this.

BUG=angleproject:1099
BUG=angleproject:1030
TEST=angle_end2end_tests,
     dEQP-GLES3.functional.attribute_location.* (10 more tests pass),
     dEQP-GLES2.functional.attribute_location.*

Change-Id: Ief047d41b0adbc238393c3c13cb29771cbb83d58
Reviewed-on: https://chromium-review.googlesource.com/329882Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>