Mark libGLESv2.so and libEGL.so as VNDK libs.

libGLESv2.so and libEGL.so are categorized as SP-NDK and
vendor_available. However, they are marked as VNDK because they
are needed by some VNDK libs.

Bug: 63866913
Test: build and boot with BOARD_VNDK_VERSION=current
Change-Id: I6552f34a1d972919f2bf1f4e4dfc81aace431b8d