Make FlushICache part of Assembler(Base) and take Isolate as parameter.

src/arm64/assembler-arm64.h

Index: src/arm64/assembler-arm64.h
diff --git a/src/arm64/assembler-arm64.h b/src/arm64/assembler-arm64.h
index a7e5a06640212544632cd2c195d2f429311e75f3..7c9c544f763657ecbb5ae2507dd8101b193960b2 100644
--- a/src/arm64/assembler-arm64.h
+++ b/src/arm64/assembler-arm64.h
@@ -810,6 +810,9 @@ class ConstPool {
 
 class Assembler : public AssemblerBase {
  public:
+  using AssemblerBase::FlushICache;
+  using AssemblerBase::FlushICacheWithoutIsolate;
+
   // Create an assembler. Instructions and relocation information are emitted
   // into a buffer, with the instructions starting from the beginning and the
   // relocation information starting from the end of the buffer. See CodeDesc
@@ -2279,7 +2282,7 @@ class PatchingAssembler : public Assembler {
     DCHECK(IsConstPoolEmpty());
     // Flush the Instruction cache.
     size_t length = buffer_size_ - kGap;
-    CpuFeatures::FlushICache(buffer_, length);
+    Assembler::FlushICacheWithoutIsolate(buffer_, length);
   }
 
   // See definition of PatchAdrFar() for details.