Removes context parameter from instruction-scoped operations (#923)

We originally had a `context.Context` for anything that might be
traced, but it turned out to be only useful for lifecycle and host functions.

For instruction-scoped aspects like memory updates, a context parameter is too
fine-grained and also invisible in practice. For example, most users will use
the compiler engine, and its memory, global or table access will never use go's
context.

Signed-off-by: Adrian Cole <adrian@tetrate.io>

internal/wasm/global_test.go

@@ -126,20 +126,18 @@ func TestGlobalTypes(t *testing.T) {
 		tc := tt
 
 		t.Run(tc.name, func(t *testing.T) {
-			for _, ctx := range []context.Context{nil, testCtx} { // Ensure it doesn't crash on nil!
-				require.Equal(t, tc.expectedType, tc.global.Type())
-				require.Equal(t, tc.expectedVal, tc.global.Get(ctx))
-				require.Equal(t, tc.expectedString, tc.global.String())
+			require.Equal(t, tc.expectedType, tc.global.Type())
+			require.Equal(t, tc.expectedVal, tc.global.Get())
+			require.Equal(t, tc.expectedString, tc.global.String())
 
-				mutable, ok := tc.global.(api.MutableGlobal)
-				require.Equal(t, tc.expectedMutable, ok)
-				if ok {
-					mutable.Set(ctx, 2)
-					require.Equal(t, uint64(2), tc.global.Get(ctx))
+			mutable, ok := tc.global.(api.MutableGlobal)
+			require.Equal(t, tc.expectedMutable, ok)
+			if ok {
+				mutable.Set(2)
+				require.Equal(t, uint64(2), tc.global.Get())
 
-					mutable.Set(ctx, tc.expectedVal) // Set it back!
-					require.Equal(t, tc.expectedVal, tc.global.Get(ctx))
-				}
+				mutable.Set(tc.expectedVal) // Set it back!
+				require.Equal(t, tc.expectedVal, tc.global.Get())
 			}
 		})
 	}