D44816 attempted to fix a few cases where clang-format incorrectly
inserted a space before the closing brace of an Objective-C dictionary
This revealed there were still a few cases where we inserted a space
after the opening brace of an Objective-C dictionary literal.
This fixes the formatting to be consistent and adds more tests.
Test Plan: New tests added. Confirmed tests failed before
diff and passed after diff. Ran tests with: % make -j12 FormatTests && ./tools/clang/unittests/Format/FormatTests