Add support for boolean ^^ operator in SPIR-V.
Add support for boolean ^^ operator in SPIR-V.

From the perspective of a SPIR-V opcode stream, ^^ is equivalent to !=,
so TK_LOGICALXOR can share the existing logic with TK_NEQ. (There are
differences in precedence and in supported types, but those were shaken
out at the IR-gen/compilation stages.)

Change-Id: I541a5ecfa603a07b256132fd1522f91941de6b20
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/338351
Commit-Queue: John Stiles <f4fcf42d3bb5924557f1eeb3be66747535e585da@google.com>
Reviewed-by: Ethan Nicholas <d2cfb8c2f603266f4dc3a6f09acbcc0089603b37@google.com>
Auto-Submit: John Stiles <f4fcf42d3bb5924557f1eeb3be66747535e585da@google.com>

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