Merge pull request #59 from martindevans/GetIndex_Accessor

Added `GetIndex` accessors (alternative to PR#58, which used properties)

Author: kelnishi

Wacs.Core/Instructions/GlobalVariable.cs

@@ -31,6 +31,8 @@ public InstGlobalGet() : base(ByteCode.GlobalGet, +1) { }
 
         private GlobalIdx Index;
 
+        public GlobalIdx GetIndex() => Index;
+
         public int LinkStackDiff => StackDiff;
 
         public bool IsConstant(IWasmValidationContext? context)
@@ -130,6 +132,8 @@ public InstGlobalSet() : base(ByteCode.GlobalSet, -1) { }
 
         private GlobalIdx Index;
 
+        public GlobalIdx GetIndex() => Index;
+
         public int LinkStackDiff => StackDiff;
 
         public bool IsConstant(IWasmValidationContext? context) =>