Some tidy warnings from core libs

Warnings reportde:

Runtime.html:
line 526 column 88 - Warning: trimming empty <p>

./jre/api/management/extension/com/sun/management/DiagnosticCommandMBean.html
line 184 column 2 - Warning: trimming empty <p>
line 240 column 2 - Warning: trimming empty <p>

./jre/api/management/extension/com/sun/management/GarbageCollectionNotificationInfo.html
line 139 column 2 - Error: <u1> is not recognized!
line 139 column 2 - Warning: discarding unexpected <u1>
line 132 column 1 - Warning: missing </div> before <li>
line 140 column 4 - Warning: inserting implicit <ul>
line 146 column 2 - Warning: discarding unexpected </u1>

./jre/api/management/extension/com/sun/management/VMOption.html
line 406 column 2 - Warning: trimming empty <p>

./jre/api/management/extension/com/sun/management/GcInfo.html
line 431 column 2 - Warning: trimming empty <p>

./jre/api/net/httpserver/spec/com/sun/net/httpserver/HttpServer.html
line 155 column 77 - Warning: trimming empty <p>
line 164 column 13 - Warning: trimming empty <p>
line 478 column 48 - Warning: trimming empty <p>

./jre/api/net/httpserver/spec/com/sun/net/httpserver/package-summary.html
line 255 column 16 - Warning: missing </pre> before </blockquote>
line 273 column 17 - Warning: discarding unexpected </pre>
line 294 column 16 - Warning: missing </pre> before </blockquote>
line 307 column 17 - Warning: discarding unexpected </pre>
line 313 column 16 - Warning: missing </pre> before </blockquote>

./jre/api/net/httpserver/spec/com/sun/net/httpserver/Filter.html
line 270 column 48 - Warning: trimming empty <p>

./jre/api/net/httpserver/spec/com/sun/net/httpserver/HttpsConfigurator.html
line 129 column 2 - Warning: missing </pre> before <blockquote>
line 150 column 2 - Warning: inserting implicit <pre>
line 128 column 2 - Warning: trimming empty <p>
line 129 column 2 - Warning: trimming empty <pre>
line 150 column 2 - Warning: trimming empty <pre>

./jre/api/net/httpserver/spec/com/sun/net/httpserver/HttpExchange.html
line 459 column 74 - Warning: trimming empty <p>
line 460 column 58 - Warning: trimming empty <p>

./jre/api/net/httpserver/spec/com/sun/net/httpserver/Headers.html
line 151 column 14 - Warning: missing </pre> before </blockquote>
line 154 column 15 - Warning: discarding unexpected </pre>

./jre/api/net/socketoptions/spec/jdk/net/NetworkPermission.html
line 132 column 2 - Warning: trimming empty <p>