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

runtime/vm/precompiler.h

Index: runtime/vm/precompiler.h
diff --git a/runtime/vm/precompiler.h b/runtime/vm/precompiler.h
index 07dfed28c9568f9d619d68ac385a11e371f7c0f8..dec16dca56941e67e32585de07b9a0381e69bcad 100644
--- a/runtime/vm/precompiler.h
+++ b/runtime/vm/precompiler.h
@@ -108,8 +108,8 @@ class FunctionKeyValueTrait {
   static inline intptr_t Hashcode(Key key) {
     // We are using pointer hash for objects originating from Kernel because
     // Fasta currently does not assign any position information to them.
-    if (key->kernel_offset() > 0) {
-      return key->kernel_offset();
+    if (key->kernel_function() != NULL) {
+      return SimplePointerHash(key->kernel_function());
     } else {
       return key->token_pos().value();
     }
@@ -137,8 +137,8 @@ class FieldKeyValueTrait {
   static inline intptr_t Hashcode(Key key) {
     // We are using pointer hash for objects originating from Kernel because
     // Fasta currently does not assign any position information to them.
-    if (key->kernel_offset() > 0) {
-      return key->kernel_offset();
+    if (key->kernel_field() != NULL) {
+      return SimplePointerHash(key->kernel_field());
     } else {
       return key->token_pos().value();
     }