fix: handle null type loc in getIndexFromLoc method (#19862)

* fix: handle `null` `loc` in `getIndexFromLoc` method

* wip: add test

Author: lumirlumir

lib/languages/js/source-code/source-code.js

@@ -795,6 +795,7 @@ class SourceCode extends TokenStore {
 	 */
 	getIndexFromLoc(loc) {
 		if (
+			loc === null ||
 			typeof loc !== "object" ||
 			typeof loc.line !== "number" ||
 			typeof loc.column !== "number"

tests/lib/languages/js/source-code/source-code.js

@@ -2311,6 +2311,11 @@ describe("SourceCode", () => {
 				/Expected `loc` to be an object with numeric `line` and `column` properties\./u,
 			);
 
+			assert.throws(
+				() => sourceCode.getIndexFromLoc(null),
+				/Expected `loc` to be an object with numeric `line` and `column` properties\./u,
+			);
+
 			assert.throws(
 				() =>
 					sourceCode.getIndexFromLoc({