RFR: JDK-8186156: Fix a11y and HTML issues in java.net and javax.net packages

[Jonathan Gibbons]

Please review the following fix for accessibility and HTML issues in the 
java.net and javax.net packages.

The only edit of note is that a table was simply removed from the top of 
URLConnection. The table was an "HTML art" depiction of actions on a 
timeline, complete with an ASCII-art time arrow. My initial reaction was 
to replace it with an ordered list ... but then I noticed the table was 
already immediately followed by the explanatory list I would have 
written. So the table was effectively redundant, and it seemd best to 
remove it.

JBS: https://bugs.openjdk.java.net/browse/JDK-8186156
Webrev: http://cr.openjdk.java.net/~jjg/8186156/webrev.00
API: http://cr.openjdk.java.net/~jjg/8186156/api.00

-- Jon