Revert "cache the creation of one GrAtlasTextOp"

This reverts commit 4b1fb7ca90a589260bf8044393a6970f947302a0.

Reason for revert: breaking chrome roll (android-pie)?

Original change's description:
> cache the creation of one GrAtlasTextOp
>
> GrAtlasTextOp has a high probability of being merged with the
> previous op. This cache keeps using the same op to merge with
> keeping memory warm.
>
> This show about 5.75% improvement in skpbench on desk_nytimes.
>
> When compiling for ios 9 or earlier, this optimization is
> disabled.
>
> Change-Id: I13ccbef6dcd4b9d82103bf20bba7d94f3e4fb6f4
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/376718
> Reviewed-by: Michael Ludwig <michaelludwig@google.com>
> Reviewed-by: Brian Salomon <bsalomon@google.com>
> Commit-Queue: Herb Derby <herb@google.com>

TBR=bsalomon@google.com,herb@google.com,michaelludwig@google.com

Change-Id: I2def6e1043dcca2fd41c40facd20b4d18971ed17
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/379840
Reviewed-by: Mike Reed <reed@google.com>
3 files changed