SPV: Support SPIR-V 1.5; five extensions no longer need OpExtension.

The generalization to addIncorporatedExtension() also fixed a 1.3
corner case with SPV_KHR_16bit_storage.

glslang/MachineIndependent/localintermediate.h

@@ -308,6 +308,12 @@ public:
         case EShTargetSpv_1_3:
             processes.addProcess("target-env spirv1.3");
             break;
+        case EShTargetSpv_1_4:
+            processes.addProcess("target-env spirv1.4");
+            break;
+        case EShTargetSpv_1_5:
+            processes.addProcess("target-env spirv1.5");
+            break;
         default:
             processes.addProcess("target-env spirvUnknown");
             break;

glslang/Public/ShaderLang.h

@@ -156,6 +156,7 @@ typedef enum {
     EShTargetSpv_1_2 = (1 << 16) | (2 << 8),          // SPIR-V 1.2
     EShTargetSpv_1_3 = (1 << 16) | (3 << 8),          // SPIR-V 1.3
     EShTargetSpv_1_4 = (1 << 16) | (4 << 8),          // SPIR-V 1.4
+    EShTargetSpv_1_5 = (1 << 16) | (5 << 8),          // SPIR-V 1.5
 } EShTargetLanguageVersion;
 
 struct TInputLanguage {