String replacements with 0 replacements should throw an error

[bbondy]

For the string replacement hacks we do in: lib/l10nUtil.js
We should throw an error for some of them if the expected number of replacements are not met.

Not for these:

        .replace(/The Chromium Authors/g, 'Brave Software Inc')
        .replace(/Google Chrome/g, 'Brave')
        .replace(/Chromium/g, 'Brave')
        .replace(/Chrome/g, 'Brave')
        .replace(/Google/g, 'Brave'), 'utf8'))

But for these:

 .replace(/<\?xml version="1.0" encoding="utf-8"\?>/i, '<?xml version="1.0" encoding="utf-8"?>\n' + autoGeneratedWarning)
        .replace('<structure name="IDR_MD_EXTENSIONS_SIDEBAR_HTML"', '<structure name="IDR_MD_EXTENSIONS_SIDEBAR_HTML" preprocess="true"')
        .replace('<structure name="IDR_SETTINGS_APPEARANCE_FONTS_PAGE_HTML"', '<structure name="IDR_SETTINGS_APPEARANCE_FONTS_PAGE_HTML" preprocess="true"')
        .replace('<structure name="IDR_SETTINGS_PASSWORDS_SECTION_HTML"', '<structure name="IDR_SETTINGS_PASSWORDS_SECTION_HTML" preprocess="true"')
        .replace('<include name="IDR_MD_HISTORY_SIDE_BAR_HTML"', '<include name="IDR_MD_HISTORY_SIDE_BAR_HTML" flattenhtml="true"')
        .replace(pageVisibility, bravePageVisibility + pageVisibility)
        .replace(/settings_chromium_strings.grdp/g, 'settings_brave_strings.grdp')