clang-format/java: Allow one-line empty functions.

clang-format/java: Allow one-line empty functions.

Before:

    void f() {
    }
    int g() {
        return 0;
    }

Now:

    void f() {}
    int g() {
        return 0;
    }

Do this by removing the explicit setting for AllowShortFunctionsOnSingleLine,
as of recently [1] it defaults to "Empty" for Java, a new setting that does
what we want.

Chromium style used to unconditionally override AllowShortFunctionsOnSingleLine
to the wrong thing, so I taught clang-format to not do that for Java files, and
while there also made -style=Chromium do the right thing for most of the
settings [2], so remove most explicit settings from this file. Except for
AllowShortFunctionsOnSingleLine, this doesn't change behavior.

1: http://llvm.org/viewvc/llvm-project?view=revision&revision=222819
2: http://llvm.org/viewvc/llvm-project?view=revision&revision=222839

BUG=429372
NOTRY=true

Review URL: https://codereview.chromium.org/757313002

Cr-Commit-Position: refs/heads/master@{#305830}