cl21: Add image access qualifier for spirv_new binaries (#272)

The OpenCL SPIR-V Environment Specification v2.2-10, Section 2.1
states that:

    For all OpTypeImage type-declaration instructions:
    The optional image Access Qualifier must be present.

Add the ReadOnly or WriteOnly qualifier as appropriate to the .spvasm
files, and regenerate the .spv files using

    spirv-as --target-env spv1.0

test_conformance/spirv_new/spirv_txt/decorate_nonreadable.spvasm32

@@ -32,7 +32,7 @@
  %3 = OpTypeVector %2 3
  %4 = OpTypePointer UniformConstant %3
  %7 = OpTypeVoid
- %8 = OpTypeImage %7 2D 0 0 0 0 Unknown
+ %8 = OpTypeImage %7 2D 0 0 0 0 Unknown WriteOnly
  %9 = OpTypeVector %2 4
 %10 = OpTypePointer CrossWorkgroup %9
 %11 = OpTypeFunction %7 %8 %10

test_conformance/spirv_new/spirv_txt/decorate_nonreadable.spvasm64

@@ -40,7 +40,7 @@
  %3 = OpTypeVector %2 3
  %4 = OpTypePointer UniformConstant %3
  %7 = OpTypeVoid
- %8 = OpTypeImage %7 2D 0 0 0 0 Unknown
+ %8 = OpTypeImage %7 2D 0 0 0 0 Unknown WriteOnly
 %10 = OpTypeVector %9 4
 %11 = OpTypePointer CrossWorkgroup %10
 %12 = OpTypeFunction %7 %8 %11

test_conformance/spirv_new/spirv_txt/decorate_nonwritable.spvasm32

@@ -41,7 +41,7 @@
 %10 = OpTypeVoid
 %11 = OpTypeVector %2 4
 %12 = OpTypePointer CrossWorkgroup %11
-%13 = OpTypeImage %10 2D 0 0 0 0 Unknown
+%13 = OpTypeImage %10 2D 0 0 0 0 Unknown ReadOnly
 %14 = OpTypeFunction %10 %12 %13
 %27 = OpTypeVector %2 2
 %31 = OpTypeSampler

test_conformance/spirv_new/spirv_txt/decorate_nonwritable.spvasm64

@@ -49,7 +49,7 @@
 %11 = OpTypeVoid
 %12 = OpTypeVector %2 4
 %13 = OpTypePointer CrossWorkgroup %12
-%14 = OpTypeImage %11 2D 0 0 0 0 Unknown
+%14 = OpTypeImage %11 2D 0 0 0 0 Unknown ReadOnly
 %15 = OpTypeFunction %11 %13 %14
 %31 = OpTypeVector %2 2
 %35 = OpTypeSampler