Use upstream Vulkan headers from external/vulkan-headers

vk_android_native_buffer.h and vk_layer_interface.h remain, since
they're Android-internal additions and not provided by the upstream
API header repository.

Bug: 129696724
Test: make checkbuild
Change-Id: If4677d08a6891b18ce347e3fa3be393fc6111fc8
Merged-In: If4677d08a6891b18ce347e3fa3be393fc6111fc8