run-bindings-tests should use 'core' or 'modules' as component_dir.

Before applying this patch, run-bindings-tests uses 'tests' as component_dir.
So tests results had '#include "bindings/tests/.../V8Test....h".

However, for testing binding modularization, need to emluate 'Source/core' and 'Source/modules'.
So Source/bindings/tests/idls/core should be treated as 'core' (i.e. the tests should be treated as if they are placed under Source/core).
Souce/bindings/tests/idsl/modules should be treated as 'modules'.

BUG=358074

Review URL: https://codereview.chromium.org/563453002

git-svn-id: svn://svn.chromium.org/blink/trunk@181875 bbb929c8-8fbe-4397-9dbb-9b2b20218538