Fix use-after-free discovered by the fuzzer.
Fix use-after-free discovered by the fuzzer.

The optimization which replaces unnecessarily nested constructors is
creating a new constructor from whole cloth, obliterating the original
constructor and its arguments. This can invalidate the definition map.
For now, this is fixed by forcing a rescan when this optimization is
applied.

Change-Id: I8a46bccf3b6422282eaf95409cd4fa50b8ad3187
Bug: oss-fuzz:29994
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/369324
Commit-Queue: John Stiles <f4fcf42d3bb5924557f1eeb3be66747535e585da@google.com>
Commit-Queue: Ethan Nicholas <d2cfb8c2f603266f4dc3a6f09acbcc0089603b37@google.com>
Auto-Submit: John Stiles <f4fcf42d3bb5924557f1eeb3be66747535e585da@google.com>
Reviewed-by: Ethan Nicholas <d2cfb8c2f603266f4dc3a6f09acbcc0089603b37@google.com>

google/skia,google/skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,google/skia,aosp-mirror/platform_external_skia,google/skia,google/skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia