tools: crash_log_parser: make ELF and MAP parameters optional

[TeroJaasko]

Description

On some bug reports the customer is providing only the raw
crash dump but not the ELF and MAP files. Those files are
needed to decode the addresses into symbol names, but the
extremely useful fault reason can still be decoded even
without them.

By making the ELF and MAP arguments optional, one can now
decode the raw dump content into something such as:

--8<--8<--

ELF or MAP file missing, logging raw values.

Crash Info:
	Crash location = <unknown-symbol> [0x000091F4] (based on PC value)
	Caller location = <unknown-symbol> [0x00018E39] (based on LR value)
	Stack Pointer at the time of crash = [200091E8]
	Target and Fault Info:
		Processor Arch: ARM-V7M or above
		Processor Variant: C24
		Forced exception, a fault with configurable priority has been escalated to HardFault
		The processor has attempted to execute an undefined instruction

Pull request type

[ ] Fix
[ ] Refactor
[ ] New target
[X] Feature
[ ] Breaking change

[theotherjimmy]

Looks good.

[0xc0170]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 2321
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/7174/

Triggering tests

/morph test
/morph uvisor-test
/morph export-build
/morph mbed2-build

[mbed-ci]

Exporter Build : SUCCESS

Build number : 1943
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/7174/

[mbed-ci]

Test : FAILURE

Build number : 2099
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/7174/2099

[cmonr]

We're looking into some CI issues at the moment. The test will be restarted when the dust has settled.

[studavekar]

re-triggering failing tests

/morph test

[mbed-ci]

Test : SUCCESS

Build number : 2144
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/7174/2144

[adustm]

Hello @TeroJaasko @0xc0170 ,
It's not clear to me. How do you generate the map file now ?
Kind regards

[TeroJaasko]

@adustm : point of this PR was not to remove need for MAP completely, but allow decoding at least some of the crash log information in case the ELF & MAP are not available at all.