Clean up encoding of size and single entry flag in Instructions.

runtime/vm/snapshot.cc

Index: runtime/vm/snapshot.cc
diff --git a/runtime/vm/snapshot.cc b/runtime/vm/snapshot.cc
index 5769ba0ad76bd08f621a0d9f7a3db1e75ba54015..427a19600ca2d3b04491b4f9269d60f27b9cc6f9 100644
--- a/runtime/vm/snapshot.cc
+++ b/runtime/vm/snapshot.cc
@@ -814,7 +814,7 @@ void AssemblyInstructionsWriter::Write(uint8_t* vmisolate_buffer,
       NoSafepointScope no_safepoint;
       uword beginning = reinterpret_cast<uword>(insns.raw()) - kHeapObjectTag;
       uword entry = beginning + Instructions::HeaderSize();
-      uword payload_size = insns.size();
+      uword payload_size = insns.Size();
       payload_size = Utils::RoundUp(payload_size, OS::PreferredCodeAlignment());
       uword end = entry + payload_size;
 
@@ -945,7 +945,7 @@ void BlobInstructionsWriter::Write(uint8_t* vmisolate_buffer,
       NoSafepointScope no_safepoint;
       uword beginning = reinterpret_cast<uword>(insns.raw()) - kHeapObjectTag;
       uword entry = beginning + Instructions::HeaderSize();
-      uword payload_size = insns.size();
+      uword payload_size = insns.Size();
       payload_size = Utils::RoundUp(payload_size, OS::PreferredCodeAlignment());
       uword end = entry + payload_size;