[ClangFormat] ObjCSpaceBeforeProtocolList should be true in the google style

Summary:
The Google style guide is neutral on whether there should be a
space before the protocol list in an Objective-C @interface or
@implementation.

The majority of Objective-C code in both Apple's public
header files and Google's open-source uses a space before
the protocol list, so this changes the google style to
default ObjCSpaceBeforeProtocolList to true.

Test Plan: make -j12 FormatTests && ./tools/clang/unittests/Format/FormatTests

Reviewers: krasimir, djasper, klimek

Reviewed By: krasimir

Subscribers: klimek, cfe-commits

Differential Revision: https://reviews.llvm.org/D41074

llvm-svn: 322873