ast_to_hir: Mark arrays as lvalues in GLSL ES, but prohibit assignment.
ast_to_hir: Mark arrays as lvalues in GLSL ES, but prohibit assignment.

This allows them to be passed as out/inout parameters, but still
prevents them from being used as the target of an assignment.  This is
per section 5.8 of the GLSL ES 1.00 specification.

jbarczak/glsl-optimizer,mapbox/glsl-optimizer,zeux/glsl-optimizer,mcanthony/glsl-optimizer,mapbox/glsl-optimizer,tokyovigilante/glsl-optimizer,zeux/glsl-optimizer,adobe/glsl2agal,benaadams/glsl-optimizer,zz85/glsl-optimizer,djreep81/glsl-optimizer,zz85/glsl-optimizer,benaadams/glsl-optimizer,djreep81/glsl-optimizer,mcanthony/glsl-optimizer,zz85/glsl-optimizer,zz85/glsl-optimizer,metora/MesaGLSLCompiler,zz85/glsl-optimizer,tokyovigilante/glsl-optimizer,dellis1972/glsl-optimizer,jbarczak/glsl-optimizer,zeux/glsl-optimizer,zeux/glsl-optimizer,bkaradzic/glsl-optimizer,wolf96/glsl-optimizer,KTXSoftware/glsl2agal,mapbox/glsl-optimizer,bkaradzic/glsl-optimizer,wolf96/glsl-optimizer,jbarczak/glsl-optimizer,metora/MesaGLSLCompiler,benaadams/glsl-optimizer,zz85/glsl-optimizer,djreep81/glsl-optimizer,adobe/glsl2agal,wolf96/glsl-optimizer,KTXSoftware/glsl2agal,adobe/glsl2agal,benaadams/glsl-optimizer,zeux/glsl-optimizer,dellis1972/glsl-optimizer,dellis1972/glsl-optimizer,tokyovigilante/glsl-optimizer,mcanthony/glsl-optimizer,benaadams/glsl-optimizer,tokyovigilante/glsl-optimizer,benaadams/glsl-optimizer,metora/MesaGLSLCompiler,wolf96/glsl-optimizer,dellis1972/glsl-optimizer,djreep81/glsl-optimizer,djreep81/glsl-optimizer,jbarczak/glsl-optimizer,bkaradzic/glsl-optimizer,bkaradzic/glsl-optimizer,tokyovigilante/glsl-optimizer,jbarczak/glsl-optimizer,KTXSoftware/glsl2agal,bkaradzic/glsl-optimizer,adobe/glsl2agal,dellis1972/glsl-optimizer,wolf96/glsl-optimizer,mapbox/glsl-optimizer,mcanthony/glsl-optimizer,mcanthony/glsl-optimizer,adobe/glsl2agal,KTXSoftware/glsl2agal,mapbox/glsl-optimizer,KTXSoftware/glsl2agal