[explicit isolates] Fix up bootstrapper Handles

Replace all implicit Handle<T>(T*) constructors in src/bootstrapper.cc
with explicit ones that use a local variable or parameter.

(All done using Leszek's awesome new tool!)

Bug: v8:7786
Change-Id: Iec01fda502dd121bc1815d5dab73bd09bb3e5aa6
Reviewed-on: https://chromium-review.googlesource.com/1107697Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53873}

src/bootstrapper.h

@@ -29,7 +29,8 @@ class SourceCodeCache final BASE_EMBEDDED {
                         bit_cast<Object**, FixedArray**>(&cache_));
   }
 
-  bool Lookup(Vector<const char> name, Handle<SharedFunctionInfo>* handle);
+  bool Lookup(Isolate* isolate, Vector<const char> name,
+              Handle<SharedFunctionInfo>* handle);
 
   void Add(Isolate* isolate, Vector<const char> name,
            Handle<SharedFunctionInfo> shared);