[M] Change in flashrom[master]: flashrom_tester: Use Path type for test data

[Edward O'Callaghan (Code Review)]

Attention is currently required from: Angel Pons, Anastasia Klimchuk, Evan Benn.

Edward O'Callaghan has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/68643 )

Change subject: flashrom_tester: Use Path type for test data
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Patch Set 3:

(3 comments)

Commit Message:

https://review.coreboot.org/c/flashrom/+/68643/comment/c07fafc8_30e0e9ab 
PS3, Line 9: Update many str types to Path.
this commit does more than just re-type data, it refactors too. refactor then re-type.

File util/flashrom_tester/src/tester.rs:

https://review.coreboot.org/c/flashrom/+/68643/comment/0dcc3081_a5b4f2be 
PS3, Line 86: layout_file: create_layout_file(rom_sz, Path::new("/tmp/"), print_layout),
adding to the TestEnv state is its own commit.

File util/flashrom_tester/src/tests.rs:

https://review.coreboot.org/c/flashrom/+/68643/comment/67137df0_36cccede 
PS3, Line 94:     info!("Calculate ROM partition sizes & Create the layout file.");
            :     let rom_sz: i64 = cmd.get_size()?;
            :     let layout_sizes = utils::get_layout_sizes(rom_sz)?;
            :     {
            :         let mut f = File::create(LAYOUT_FILE)?;
            :         let mut buf: Vec<u8> = vec![];
            :         utils::construct_layout_file(&mut buf, &layout_sizes)?;
            : 
            :         f.write_all(&buf)?;
            :         if print_layout {
            :             info!(
            :                 "Dumping layout file as requested:\n{}",
            :                 String::from_utf8_lossy(&buf)
            :             );
            :         }
            :     }
moving this should be it's own commit.