Verify Pattern, step 1: Integrate doc changes from 7u40 to 8u121-b13

Between OpenJDK 7u40 and 8u121-b13, documentation in Pattern.java was
refactored; for example, documentation previously listed under
"Predefined character classes (Unicode character)" for the classes
\h, \H, \v, \V, \R has been moved into the sections "Predefined character
classes" (\h, \H, \v, \V) and "Linebreak matcher" (\R).

These refactorings (which don't affect the semantics of the documentation)
were not previously integrated into Android's Pattern.java. This CL
integrates those changes.

A couple of minor other local formatting/whitespace differences are
reverted in this CL.

This CL does NOT add missing change markers nor does it verify whether
the existing changes (generally in areas of this file not touched by
OpenJDK 7u40->8u121-b13) are correct / deliberate; it also does not
integrate a behavior change of Pattern.split() nor documentation
around \p{IsJoin_Control}. There are left to follow-up CLs.

Bug: 109659282
Test: Treehugger

Change-Id: I6c7eee4e7e8dc304ce58d464920a1ce1cc1a19bb
1 file changed