Do not copy vulkan-1.dll to Win bots.

Previously, we needed vulkan-1.dll from the Vulkan runtime because some
drivers did not include the Vulkan loader. Now, all drivers include this
DLL and using the version from assets causes problems for newer Intel
drivers.

Bug: skia:7490
Change-Id: I7bd37fb0d2c88a4753f354ab2bc88761562ced2f
Reviewed-on: https://skia-review.googlesource.com/107060
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Ben Wagner <benjaminwagner@google.com>
54 files changed