Only warn about variables being shadowed in inline assembly.

test/libsolidity/syntaxTests/inlineAssembly/shadowing/global_function_by_opcode.sol

@@ -0,0 +1,8 @@
+function mload() pure {}
+contract C {
+    function g() public pure {
+        assembly {
+        }
+    }
+}
+// ----

test/libsolidity/syntaxTests/inlineAssembly/shadowing/local_function_by_opcode.sol

@@ -0,0 +1,9 @@
+contract C {
+    function add(uint, uint) public pure returns (uint) { return 7; }
+    function g() public pure returns (uint x, uint y) {
+        x = add(1, 2);
+        assembly {
+            y := add(1, 2)
+        }
+    }
+}

test/libsolidity/syntaxTests/inlineAssembly/shadowing/state_variable_by_opcode.sol

@@ -0,0 +1,8 @@
+contract C {
+    uint mload;
+    function g() public pure {
+        assembly {
+        }
+    }
+}
+// ----

test/libsolidity/syntaxTests/inlineAssembly/shadowing/variable_by_opcode.sol

@@ -9,6 +9,5 @@ contract C {
     }
 }
 // ----
-// Warning 8261: (109-119): Variable is shadowed in inline assembly by an instruction of the same name
 // Warning 2072: (52-62): Unused local variable.
 // Warning 2072: (109-119): Unused local variable.