t/t3437: fixup here-docs in the 'setup' test

t/t3437: fixup here-docs in the 'setup' test

The most common way to format here-docs in Git test scripts is for the
body and EOF to be indented the same amount as the command which opened
the here-doc. Fix a few here-docs in this script to conform to that
standard and also remove the unnecessary curly braces.

Mentored-by: Christian Couder <redacted>
Mentored-by: Phillip Wood <redacted>
Helped-by: Eric Sunshine <redacted>
Signed-off-by: Charvi Mendiratta <redacted>
Signed-off-by: Junio C Hamano <redacted>