[Runtime] Remove obsolete constants.

Remove now obsolete constants (see https://chromium.googlesource.com/v8/v8/+/8f0bf07b504e8bb27ef3703388c4c0699670331f)
from postmortem metadata generator.

BUG=

Review-Url: https://codereview.chromium.org/2636863004
Cr-Commit-Position: refs/heads/master@{#42374}

tools/gen-postmortem-metadata.py

@@ -93,10 +93,6 @@ consts_misc = [
 
     { 'name': 'prop_idx_first',
         'value': 'DescriptorArray::kFirstIndex' },
-    { 'name': 'prop_type_field',
-        'value': 'DATA' },
-    { 'name': 'prop_type_const_field',
-        'value': 'DATA_CONSTANT' },
     { 'name': 'prop_type_mask',
         'value': 'PropertyDetails::TypeField::kMask' },
     { 'name': 'prop_index_mask',