Added utility scripts for running oprofile

Added utility scripts for running oprofile in tools/oprofile. 

To profile running the JavaScript file test.js using the V8 release mode shell (assuming it is build passing prof=oprofile to the SCons build). The following commands can be used:

$ tools/oprofile/start
$ tools/oprofile/run test.js
$ tools/oprofile/report | less
$ tools/oprofile/annotate | less
$ tools/oprofile/shutdown

Here is a summary of the commands.

For all the commands taking an executable the executable is expected to be a binary using V8. If no executable is specified the release mode V8 shell is assumed.

By default the --session-dir=/tmp/oprofv8 is passed to all oprofile commands. This walue can be changed by setting environment variable OPROFILE_SESSION_DIR.

When using the defaulf executable (V8 shell in release mode) it is assumed to be located in ../.. relative from the oprofile utility scripts. This default location can be overridden using the V8_SHELL_DIR environment variable.

start
-----
Start the oprofiling daemon.

run [executable] [parameters]
-----------------------------
Profile a V8 executable. Running this will reset oprofile samples, run the command and do an oprofile dump to flush samples and write ELF binaries for the generated code. The parameters are passed to the executable together with the --oprofile option.

report [executable] [parameters]
--------------------------------
Print the report for a profile run. The parameters are passed to opreport. E.g report --callgraph.

annotate [executable] [parameters]
----------------------------------
Print annotated assembly for a profile run. The parameters are passed to opannotate. E.g annotate -threshold 1.

reset
-----
Reset oprofile samples.

dump
----
Flush oprofile samples and write ELF binaries for the generated code.

shutdown
--------
Shutdown oprofile daemon.

Added a warning which is printed if option --oprofile is passed to a V8 which has not been compiled with oprofile support.

Committed: http://code.google.com/p/v8/source/detail?r=2186

[Mikhail Naganov, 2009-06-16 11:54:04]

LGTM with a suggestion.

http://codereview.chromium.org/125181/diff/1011/25
File tools/oprofile/common (right):

http://codereview.chromium.org/125181/diff/1011/25#newcode5
Line 5: 
Maybe add an alias for 'sudo opcontrol --session-dir="$OPROFILE_SESSION_DIR"' in
this script?

[Søren Thygesen Gjesse, 2009-06-16 12:08:15]

http://codereview.chromium.org/125181/diff/1011/25
File tools/oprofile/common (right):

http://codereview.chromium.org/125181/diff/1011/25#newcode5
Line 5: 
On 2009/06/16 11:54:04, Mikhail Naganov wrote:
> Maybe add an alias for 'sudo opcontrol --session-dir="$OPROFILE_SESSION_DIR"'
in
> this script?

Added alias sudo_opcontrol.