Revert "[clang-format] Set SeparateDefinitionBlocks=Always"

This reverts commit d38565f.

It added blank lines between one line member function definitions
inside class bodies/header files, something which is undesirable.

.clang-format

@@ -174,7 +174,7 @@ RemoveParentheses: Leave
 RemoveSemicolon: false
 RequiresClausePosition: OwnLine
 RequiresExpressionIndentation: OuterScope
-SeparateDefinitionBlocks: Always
+SeparateDefinitionBlocks: Leave
 ShortNamespaceLines: 1
 SkipMacroDefinitionBody: false
 SortIncludes: CaseSensitive