Minor improvements to SymbolTable::addWithoutOwnership.
Minor improvements to SymbolTable::addWithoutOwnership.

These changes aren't on the critical path, so this doesn't lead to a
measurable speed boost, but this code does a bit less work in the
FunctionDeclaraction/UnresolvedFunction cases, and is flattened out a
bit for easier readability.

Change-Id: I105a1a0b1d02c9ec87f6f874437ddf1a53d9be0c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/322456
Commit-Queue: John Stiles <f4fcf42d3bb5924557f1eeb3be66747535e585da@google.com>
Commit-Queue: Brian Osman <794c0b5534edf5601d88e1d41975d0262da12894@google.com>
Auto-Submit: John Stiles <f4fcf42d3bb5924557f1eeb3be66747535e585da@google.com>
Reviewed-by: Brian Osman <794c0b5534edf5601d88e1d41975d0262da12894@google.com>

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