git: openjdk/jdk-sandbox: jdk.javadoc/snippets: Exclude snippet-files from java.base Java.gmk

[Jonathan Gibbons]

Changeset: f8b1ce20
Author:    Jonathan Gibbons <jonathan.gibbons at oracle.com>
Date:      2021-05-06 11:33:48 +0000
URL:       https://git.openjdk.java.net/jdk-sandbox/commit/f8b1ce20e40fc6a6417520e4950b4fefd296a21a

Exclude snippet-files from java.base Java.gmk
Move java/util/snippet-files/java/util/MapSnippets.java to java/util/snippet-files/MapSnippets.java

! make/modules/java.base/Java.gmk
! src/java.base/share/classes/java/util/Map.java
= src/java.base/share/classes/java/util/snippet-files/MapSnippets.java