Support Uint to Int implicit conversions at #extension GL_ARB_gpu_shader5.

Signed-off-by: ZhiqianXia <xzq0528@outlook.com>

glslang/MachineIndependent/localintermediate.h

@@ -926,6 +926,11 @@ public:
         return false;
     }
 
+    bool IsRequestedExtension(const char* extension) const
+    {
+        return (requestedExtensions.find(extension) != requestedExtensions.end());
+    }
+
     void addToCallGraph(TInfoSink&, const TString& caller, const TString& callee);
     void merge(TInfoSink&, TIntermediate&);
     void finalCheck(TInfoSink&, bool keepUncalled);