Bug 1445011: Include sourceName in error report payload. r=Gijs

The module attribute for an exception is surfaced in Sentry as the "transaction"
tag, and is useful for errors that don't include stack traces.

Differential Revision: https://phabricator.services.mozilla.com/D727

MozReview-Commit-ID: JKwgmE2jBXB

--HG--
extra : rebase_source : af817b5709e5b596885cc1674bcaaf7f96a0a48f
extra : amend_source : 8b7820ca53c29429ea9d788b1cf84012c99fdf81

browser/modules/BrowserErrorReporter.jsm

@@ -170,6 +170,7 @@ class BrowserErrorReporter {
           {
             type: errorName,
             value: errorMessage,
+            module: message.sourceName,
             stacktrace: {
               frames,
             }

browser/modules/test/browser/browser_BrowserErrorReporter.js

@@ -366,6 +366,7 @@ add_task(async function testFetchArguments() {
           {
             type: "Error",
             value: "testFetchArguments error",
+            module: testPageUrl,
             stacktrace: {
               frames: [
                 {