Break some fuzzer targets out so oss-fuzz can use them

FuzzImageFilterDeserialize is already being used in oss-fuzz
but the target lived there and not here.  This moves it here.

Then we can turn on:
 - FuzzPathDeserialize
 - FuzzTextBlobDeserialize


Bug: skia:
Change-Id: I7baee8386fb7aeebc43a68abfff9a670ba16f82c
Reviewed-on: https://skia-review.googlesource.com/105763
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Kevin Lubick <kjlubick@google.com>
diff --git a/BUILD.gn b/BUILD.gn
index 47f8d84..12c6bad 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -1728,8 +1728,11 @@
       "fuzz/FuzzPathop.cpp",
       "fuzz/FuzzScaleToSides.cpp",
       "fuzz/fuzz.cpp",
+      "fuzz/oss_fuzz/FuzzImageFilterDeserialize.cpp",
+      "fuzz/oss_fuzz/FuzzPathDeserialize.cpp",
       "fuzz/oss_fuzz/FuzzRegionDeserialize.cpp",
       "fuzz/oss_fuzz/FuzzRegionSetPath.cpp",
+      "fuzz/oss_fuzz/FuzzTextBlobDeserialize.cpp",
       "tools/UrlDataManager.cpp",
       "tools/debugger/SkDebugCanvas.cpp",
       "tools/debugger/SkDrawCommand.cpp",