[kernel] Stream everything. Replace .kernel_function with .kernel_offset

pkg/kernel/binary.md

 This file describes the binary format of Dart Kernel.
 
 Notation
 --------
 Bitmasks are described with the syntax:
 ```scala
     Byte flags (flag1, flag2, ..., flagN)
 ```
 where 'flag<N>' is the N-th least significant bit,
 (so flag1 is the least significant bit).
@@ skipping 299 matching lines @@
 */
 
 type FunctionNode {
   Byte tag = 3;
   FileOffset fileOffset;
   FileOffset fileEndOffset;
   Byte asyncMarker; // Index into AsyncMarker above.
   Byte dartAsyncMarker; // Index into AsyncMarker above.
   List<TypeParameter> typeParameters;
   UInt requiredParameterCount;
+  UInt totalParameterCount; // positionalParameters.length + namedParameters.length.

[Kevin Millikin (Google), 2017/06/12 12:01:51]

For some reason it seems more obvious to have the parameter count before the
required parameter count.  And I'd just call it 'parameterCount' which seems to
obviously include all the parameters.

[jensj, 2017/06/13 13:42:14]

Done.

   List<VariableDeclaration> positionalParameters;
   List<VariableDeclaration> namedParameters;
   DartType returnType;
   Option<Statement> body;
 }
 
 type VariableReference {
   // Reference to the Nth variable in scope, with 0 being the
   // first variable declared in the outermost scope, and larger
   // numbers being the variables declared later in a given scope,
@@ skipping 645 matching lines @@
   Byte tag = 88;
 }
 
 type TypeParameter {
   // Note: there is no tag on TypeParameter
   StringReference name; // Cosmetic, may be empty, not unique.
   DartType bound; // 'dynamic' if no explicit bound was given.
 }
 
 ```