fix broken links in java.base docs

A few files in java.base have broken links caused by the change to use HTML5 instead of HTML 4, and the corresponding change in the way that javadoc encodes the anchors for method names.

src/java.base/share/classes/java/net/doc-files/net-properties.html
src/java.base/share/classes/java/util/doc-files/coll-designfaq.html
src/java.base/share/classes/java/util/doc-files/coll-overview.html
src/java.base/share/classes/java/util/doc-files/coll-reference.html