lib: don't match sourceMappingURL in strings

Prior to this change `sourceMappingURL` in string where being matched
by the RegExp which caused sourcemaps not be loaded when using the
`--enable-source-maps` flag. This commit changes the RegExp to match
the last occurrence.

Fixes: #44654

lib/internal/source_map/source_map_cache.js

@@ -41,8 +41,8 @@ const esmSourceMapCache = new SafeMap();
 // The generated sources is not mutable, so we can use a Map without memory concerns:
 const generatedSourceMapCache = new SafeMap();
 const kLeadingProtocol = /^\w+:\/\//;
-const kSourceMappingURLMagicComment = /\/[*/]#\s+sourceMappingURL=(?<sourceMappingURL>[^\s]+)/;
-const kSourceURLMagicComment = /\/[*/]#\s+sourceURL=(?<sourceURL>[^\s]+)/;
+const kSourceMappingURLMagicComment = /\/[*/]#\s+sourceMappingURL=(?<sourceMappingURL>[^\s]+)[\s]*$/;
+const kSourceURLMagicComment = /\/[*/]#\s+sourceURL=(?<sourceURL>[^\s]+)[\s]*$/;
 
 const { fileURLToPath, pathToFileURL, URL } = require('internal/url');
 let SourceMap;

test/message/source_map_sourcemapping_url_string.js

@@ -0,0 +1,13 @@
+// Flags:  --enable-source-maps
+
+'use strict';
+require('../common');
+Error.stackTraceLimit = 2;
+
+try {
+  require('../fixtures/source-map/typescript-sourcemapping_url_string');
+} catch (err) {
+  setTimeout(() => {
+    console.info(err);
+  }, 10);
+}

test/message/source_map_sourcemapping_url_string.out

@@ -0,0 +1,3 @@
+reachable
+Error: an exception
+    at *typescript-sourcemapping_url_string.ts:3:7*