Fold MSAN awareness into SkJumper.cpp.

This is preparation for removing skia_enable_jumper, making it true.

CQ_INCLUDE_TRYBOTS=skia.primary:Test-Ubuntu-Clang-GCE-CPU-AVX2-x86_64-Debug-MSAN

Change-Id: I21763ea5ebafaaddda7056176796307f1a81d722
Reviewed-on: https://skia-review.googlesource.com/8830
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
diff --git a/BUILD.gn b/BUILD.gn
index f4298be..8aaa913 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -29,7 +29,7 @@
   skia_enable_android_framework_defines = false
   skia_enable_discrete_gpu = true
   skia_enable_effects = true
-  skia_enable_jumper = is_skia_standalone && sanitize != "MSAN"
+  skia_enable_jumper = is_skia_standalone
   skia_enable_gpu = true
   skia_enable_pdf = true
   skia_enable_tools = is_skia_standalone