Add more tests to ViewPureChecker

test/libsolidity/syntaxTests/viewPureChecker/address.sol

@@ -0,0 +1,8 @@
+contract C {
+    function f() public view returns (uint) {
+        return address(this).balance;
+    }
+    function g() public view returns (uint) {
+        return address(0).balance;
+    }
+}

test/libsolidity/syntaxTests/viewPureChecker/assembly.sol

@@ -14,10 +14,16 @@ contract C {
     function h() view public {
         assembly { function g() { pop(blockhash(20)) } }
     }
-    function j() public {
+    function i() public {
         assembly { pop(call(0, 1, 2, 3, 4, 5, 6)) }
     }
-    function k() public {
+    function j() public {
         assembly { pop(call(gas(), 1, 2, 3, 4, 5, 6)) }
     }
+    function k() public view {
+        assembly { pop(balance(0)) }
+    }
+    function l() public view {
+        assembly { pop(extcodesize(0)) }
+    }
 }

test/libsolidity/syntaxTests/viewPureChecker/assembly_constantinople.sol

@@ -0,0 +1,8 @@
+contract C {
+    function f() public view {
+        assembly { pop(extcodehash(0)) }
+    }
+}
+// ====
+// EVMVersion: >=constantinople
+// ----

test/libsolidity/syntaxTests/viewPureChecker/assembly_istanbul.sol

@@ -0,0 +1,8 @@
+contract C {
+    function f() public pure {
+        assembly { pop(chainid()) }
+    }
+}
+// ====
+// EVMVersion: >=istanbul
+// ----