Adding event and error selector fields on the lines of the function selector fields

test/libsolidity/semanticTests/error/error_selector.sol

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+library L {
+    error E();
+}
+library S {
+    error E(uint);
+}
+library T {
+    error E();
+}
+
+error E();
+
+interface I {
+    error E();
+    function f() external pure;
+}
+
+contract D {
+    error F();
+}
+
+contract C is D {
+    function test1() public pure returns (bytes4, bytes4, bytes4, bytes4) {
+        assert(L.E.selector == T.E.selector);
+        assert(L.E.selector != S.E.selector);
+        assert(E.selector == L.E.selector);
+        assert(I.E.selector == L.E.selector);
+        return (L.E.selector, S.E.selector, E.selector, I.E.selector);
+    }
+
+    bytes4 s1 = L.E.selector;
+    bytes4 s2 = S.E.selector;
+    bytes4 s3 = T.E.selector;
+    bytes4 s4 = I.E.selector;
+    function test2() external returns (bytes4, bytes4, bytes4, bytes4) {
+        return (s1, s2, s3, s4);
+    }
+
+    function test3() external returns (bytes4) {
+        return (F.selector);
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// test1() -> 0x92bbf6e800000000000000000000000000000000000000000000000000000000, 0x2ff06700000000000000000000000000000000000000000000000000000000, 0x92bbf6e800000000000000000000000000000000000000000000000000000000, 0x92bbf6e800000000000000000000000000000000000000000000000000000000
+// test2() -> 0x92bbf6e800000000000000000000000000000000000000000000000000000000, 0x2ff06700000000000000000000000000000000000000000000000000000000, 0x92bbf6e800000000000000000000000000000000000000000000000000000000, 0x92bbf6e800000000000000000000000000000000000000000000000000000000
+// test3() -> 0x28811f5900000000000000000000000000000000000000000000000000000000