[clang-format] Don't derive pointer alignment

In V8, we always want the pointer alignment to be left, i.e. "Foo* foo"
instead of "Foo *foo".

R=jochen@chromium.org
NOTRY=true

Review-Url: https://codereview.chromium.org/2631183002
Cr-Commit-Position: refs/heads/master@{#42390}

.clang-format

 # Defines the Google C++ style for automatic reformatting.
 # http://clang.llvm.org/docs/ClangFormatStyleOptions.html
 BasedOnStyle: Google
+DerivePointerAlignment: false
 MaxEmptyLinesToKeep: 1