Previously GetSharedFunctionInfoForStreamedScript didn't either check the
compilation cache or put the result of compilation into the compilation
cache. This would mean future compiles would need to re-parse / compile
the same script even if the isolate had already seen it. This CL
fixes this.

BUG=v8:5203

Change-Id: I421627b80848feb9884e2440c4ee66556e05b3c9
Reviewed-on: https://chromium-review.googlesource.com/924285
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Mythri Alle <mythria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51469}