Perf Tests: Set up branch only once for all test suites

[ockham]

Description

@youknowriad notified me via DM that

we run first the post editor tests on both branches and then the site editor perf tests on both branches
it seems that we lose a lot of time building and installing deps when doing so instead it’d be better if we run both suites in a branch before switching branches

This is because my recent PR #23842 got the loop nesting order wrong. This PR fixes this issue.

How has this been tested?

In the details for the Performance test GH Action on this PR, verify that a branch is only checked out once, and both test suites are run on it, before the next branch is checked out (cutting down overall running time of the Action). Verify that the results are still sane 👍

Types of changes

Performance test performance improvement 😬

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.
• I've updated all React Native files affected by any refactorings/renamings in this PR.

[github-actions]

Size Change: 0 B

Total Size: 1.15 MB

ℹ️ View Unchanged

Filename	Size	Change
build/a11y/index.min.js	1.14 kB	0 B
build/annotations/index.min.js	3.67 kB	0 B
build/api-fetch/index.min.js	3.43 kB	0 B
build/autop/index.min.js	2.82 kB	0 B
build/blob/index.min.js	620 B	0 B
build/block-directory/index.min.js	7.63 kB	0 B
build/block-directory/style-rtl.css	953 B	0 B
build/block-directory/style.css	952 B	0 B
build/block-editor/index.min.js	125 kB	0 B
build/block-editor/style-rtl.css	10.8 kB	0 B
build/block-editor/style.css	10.8 kB	0 B
build/block-library/editor-rtl.css	7.61 kB	0 B
build/block-library/editor.css	7.61 kB	0 B
build/block-library/index.min.js	132 kB	0 B
build/block-library/style-rtl.css	7.82 kB	0 B
build/block-library/style.css	7.83 kB	0 B
build/block-library/theme-rtl.css	728 B	0 B
build/block-library/theme.css	729 B	0 B
build/block-serialization-default-parser/index.min.js	1.88 kB	0 B
build/block-serialization-spec-parser/index.min.js	3.1 kB	0 B
build/blocks/index.min.js	48.3 kB	0 B
build/components/index.min.js	200 kB	0 B
build/components/style-rtl.css	15.7 kB	0 B
build/components/style.css	15.6 kB	0 B
build/compose/index.min.js	9.68 kB	0 B
build/core-data/index.min.js	11.5 kB	0 B
build/data-controls/index.min.js	1.29 kB	0 B
build/data/index.min.js	8.45 kB	0 B
build/date/index.min.js	5.38 kB	0 B
build/deprecated/index.min.js	772 B	0 B
build/dom-ready/index.min.js	568 B	0 B
build/dom/index.min.js	3.23 kB	0 B
build/edit-navigation/index.min.js	10.8 kB	0 B
build/edit-navigation/style-rtl.css	1.08 kB	0 B
build/edit-navigation/style.css	1.08 kB	0 B
build/edit-post/index.min.js	304 kB	0 B
build/edit-post/style-rtl.css	5.61 kB	0 B
build/edit-post/style.css	5.61 kB	0 B
build/edit-site/index.min.js	16.9 kB	0 B
build/edit-site/style-rtl.css	3.06 kB	0 B
build/edit-site/style.css	3.06 kB	0 B
build/edit-widgets/index.min.js	9.37 kB	0 B
build/edit-widgets/style-rtl.css	2.45 kB	0 B
build/edit-widgets/style.css	2.45 kB	0 B
build/editor/editor-styles-rtl.css	537 B	0 B
build/editor/editor-styles.css	539 B	0 B
build/editor/index.min.js	45.3 kB	0 B
build/editor/style-rtl.css	3.78 kB	0 B
build/editor/style.css	3.78 kB	0 B
build/element/index.min.js	4.65 kB	0 B
build/escape-html/index.min.js	733 B	0 B
build/format-library/index.min.js	7.72 kB	0 B
build/format-library/style-rtl.css	547 B	0 B
build/format-library/style.css	548 B	0 B
build/hooks/index.min.js	2.13 kB	0 B
build/html-entities/index.min.js	621 B	0 B
build/i18n/index.min.js	3.56 kB	0 B
build/is-shallow-equal/index.min.js	711 B	0 B
build/keyboard-shortcuts/index.min.js	2.51 kB	0 B
build/keycodes/index.min.js	1.94 kB	0 B
build/list-reusable-blocks/index.min.js	3.12 kB	0 B
build/list-reusable-blocks/style-rtl.css	476 B	0 B
build/list-reusable-blocks/style.css	476 B	0 B
build/media-utils/index.min.js	5.32 kB	0 B
build/notices/index.min.js	1.79 kB	0 B
build/nux/index.min.js	3.4 kB	0 B
build/nux/style-rtl.css	671 B	0 B
build/nux/style.css	668 B	0 B
build/plugins/index.min.js	2.56 kB	0 B
build/primitives/index.min.js	1.4 kB	0 B
build/priority-queue/index.min.js	789 B	0 B
build/redux-routine/index.min.js	2.85 kB	0 B
build/rich-text/index.min.js	13.9 kB	0 B
build/server-side-render/index.min.js	2.71 kB	0 B
build/shortcode/index.min.js	1.7 kB	0 B
build/token-list/index.min.js	1.27 kB	0 B
build/url/index.min.js	4.06 kB	0 B
build/viewport/index.min.js	1.85 kB	0 B
build/warning/index.min.js	1.14 kB	0 B
build/wordcount/index.min.js	1.17 kB	0 B

_{compressed-size-action}

[noahtallen]

LGTM, but I'd also wait for riad to take a look.

[youknowriad]

Looks good. Thanks for the update @ockham