Roll Skia from 621fe29616b5 to ec0be312d3d3 (4 revisions)

https://skia.googlesource.com/skia.git/+log/621fe29616b5..ec0be312d3d3

2024-01-16 michaelludwig@google.com Update SkVx to_half to support denormals,overflow, and RTNE
2024-01-16 jvanverth@google.com GrRRectEffect: return failure if nine-patch corners are invalid
2024-01-16 johnstiles@google.com Fix fuzzer-discovered error with duplicate symbols.
2024-01-16 johnstiles@google.com Switch to unique_ptr<> for SymbolTable management.

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://skia-autoroll.corp.goog/r/android-master-autoroll
Please CC djsollen@google.com,nscobie@google.com,rmistry@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://issues.skia.org/issues/new?component=1389291&template=1850622

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

Test: Presubmit checks will test this change.
Exempt-From-Owner-Approval: The autoroll bot does not require owner approval.
Bug: b/186777432
Change-Id: Ibd685d8340930ea495555f6a1266978001412cf2