A few options and features have been added to the tool:

* an output file might be specified using --output=file.name
* a shortcut when the output file is also the input, which is handy
   when fixing golden files, --rebaseline.
* the input snippet might be optionally not wrapped in a top function,
   or not executed after compilation (--no-wrap and --no-execute).
* the name of the wrapper can be configured using --wrapper-name=foo

The same options can be configured via setters on the usual
BytecodeExpectationsPrinter.

The output file now includes all the relevant flags to reproduce it
when running again through the tool (usually with --rebaseline).

In particular, when running in --rebaseline mode, options from the
file header will override options specified in the command line.

A couple of other fixes and improvements:

* description of the handlers is now emitted (closing the TODO).
* the snippet is now correctly unquoted when double quotes are used.
* special registers (closure, context etc.) are now emitted as such,
   instead of displaying their numeric value.
* the tool can now process top level code as well.

BUG=v8:4280
LOG=N

Review URL: https://codereview.chromium.org/1698403002

Cr-Commit-Position: refs/heads/master@{#34152}