Revert "Only use flat varyings for integer texIndex."
Revert "Only use flat varyings for integer texIndex."

This reverts commit eadb9f9a559d559b55831d6ba6636d1b4d2d47c7.

Reason for revert: Causing issues with NexusPlayer Vulkan.

Original change's description:
> Only use flat varyings for integer texIndex.
> 
> Flat varyings aren't supported with ES 2.0, so just
> fall back to non-flat if we can only handle float.
> 
> Change-Id: Id47a773b86666c46916efe5bcb1c629743977ccf
> Reviewed-on: https://skia-review.googlesource.com/73800
> Reviewed-by: Brian Salomon <bsalomon@google.com>
> Commit-Queue: Jim Van Verth <509afb0bfbb23ecaaf1fb3323209f531b45e75a6@google.com>

TBR=509afb0bfbb23ecaaf1fb3323209f531b45e75a6@google.com,bsalomon@google.com

Change-Id: I5becf5addea1f0bd1ef0fd100d1fc8fd3c503f91
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/74000
Reviewed-by: Jim Van Verth <509afb0bfbb23ecaaf1fb3323209f531b45e75a6@google.com>
Commit-Queue: Jim Van Verth <509afb0bfbb23ecaaf1fb3323209f531b45e75a6@google.com>

HalCanary/skia-hc,google/skia,google/skia,rubenvb/skia,aosp-mirror/platform_external_skia,rubenvb/skia,rubenvb/skia,rubenvb/skia,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,google/skia,rubenvb/skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,rubenvb/skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,google/skia,google/skia,rubenvb/skia,google/skia,google/skia,aosp-mirror/platform_external_skia,Hikari-no-Tenshi/android_external_skia,Hikari-no-Tenshi/android_external_skia,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,rubenvb/skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,rubenvb/skia,google/skia,google/skia,HalCanary/skia-hc,rubenvb/skia,Hikari-no-Tenshi/android_external_skia,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,HalCanary/skia-hc,google/skia,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia