Adds some more tests and groups all function call inheritance related together into single sub-directory.

test/libsolidity/semanticTests/functionCall/inheritance/call_base.sol

@@ -0,0 +1,13 @@
+contract Base {
+	function f(uint n) public returns (uint) {
+		return 2 * n;
+	}
+}
+
+contract Child is Base {
+	function g(uint n) public returns (uint) {
+		return f(n);
+	}
+}
+// ----
+// g(uint256): 4 -> 8

test/libsolidity/semanticTests/functionCall/inheritance/call_base_base.sol

@@ -0,0 +1,27 @@
+contract BaseBase {
+	function f(uint n) public virtual returns (uint) {
+		return 2 * n;
+	}
+	function s(uint n) public returns (uint) {
+		return 4 * n;
+	}
+}
+
+contract Base is BaseBase {
+	function f(uint n) public virtual override returns (uint) {
+		return 3 * n;
+	}
+}
+
+contract Child is Base {
+	function g(uint n) public returns (uint) {
+		return f(n);
+	}
+
+	function h(uint n) public returns (uint) {
+		return s(n);
+	}
+}
+// ----
+// g(uint256): 4 -> 12
+// h(uint256): 4 -> 16

test/libsolidity/semanticTests/functionCall/inheritance/call_base_base_explicit.sol

@@ -0,0 +1,30 @@
+contract BaseBase {
+	function f(uint n) public virtual returns (uint) {
+		return 2 * n;
+	}
+
+	function s(uint n) public returns (uint) {
+		return 4 * n;
+	}
+}
+
+contract Base is BaseBase {
+	function f(uint n) public virtual override returns (uint) {
+		return 3 * n;
+	}
+}
+
+contract Child is Base {
+	function g(uint n) public returns (uint) {
+		// calling base-bse function of a virtual overridden function.
+		return BaseBase.f(n);
+	}
+
+	function k(uint n) public returns (uint) {
+		// Calling base-base function of a non-virtual function.
+		return BaseBase.s(n);
+	}
+}
+// ----
+// g(uint256): 4 -> 8
+// k(uint256): 4 -> 16

test/libsolidity/semanticTests/functionCall/inheritance/call_base_explicit.sol

@@ -0,0 +1,14 @@
+contract Base {
+	function f(uint n) public returns (uint) {
+		return 2 * n;
+	}
+}
+
+contract Child is Base {
+	function g(uint n) public returns (uint) {
+		return Base.f(n);
+	}
+}
+// ----
+// g(uint256): 4 -> 8
+