Remove java version checks

The build now uses a prebuilt javac binary distributed with the
source, checking the host java version is no longer required.

Reapplies Ieef83481d0e6d68371bbd8a422f870ffe2bbb428 after updating
some more manifests to include the prebuilts.

Test: m -j checkbuild
Bug: 62956999
Change-Id: I774dbb75c8ae2ff1a990423a3827c77886e44779
(cherry picked from commit c6f07f00da)

ui/build/Android.bp

@@ -27,7 +27,6 @@ bootstrap_go_package {
         "context.go",
         "environment.go",
         "exec.go",
-        "java.go",
         "kati.go",
         "make.go",
         "ninja.go",