Disable exceptions on Windows also in the shared_library build

Disable exceptions on Windows also in the shared_library build

They were previously only disabled in static_library builds. This is believed
to have been due to problems with old MSVC versions, but it should work now.

This change is relevant for Clang, which currently doesn't support exceptions
on Windows.

Last time I attempted to do this, it broke some tests due to a debug assertion.
Gtest had previously been catching the exception, but with exceptions disabled
it crashed. Those tests were actually broken in static_library Debug builds
too, but we don't seem to have bots for that. After Blink r176189, we no longer
hit that debug assertion, so the tests now pass.

BUG=82385
TEST=blink_platform_unittests --gtest_filter=DateTimeFormatTest.CommonPattern,
     content_browsertests --gtest_filter=RenderViewImplTest.SetEditableSelectionAndComposition
     webkit_unit_tests

R=thakis@chromium.org

Review URL: https://codereview.chromium.org/404853002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@284519 0039d316-1c4b-4281-b951-d872f2087c98