Directly link to external documentation.

This CL was created by a String search&replace across libcore/ojluni
.java and .html files. After this CL, the String "openjdk-redirect"
no longer occurs anywhere in ojluni.

The redirection through openjdk-redirect.html no longer works because
a security policy limits what the JavaScript can do. This CL changes
the links to go directly to an external site rather than through
openjdk-redirect.html.

Bug: 126658789
Test: Manually checked for a handful of links that the link target exists.
Test: Performed a full-text search to verify that after this CL, there
      are no more occurrences of the string "openjdk-redirect" in ojluni.

(cherry picked from commit f462b9e21ee962db0e313a13df4c0a74cd0e466e)

Change-Id: Ie3035e89cecf22f5ef6f32163082802732d0e12e
Merged-In: Ie3035e89cecf22f5ef6f32163082802732d0e12e