git: openjdk/leyden: premain: Added "make mainline_vs_premain" to get simple comparisons of pet clinic

[duke]

Changeset: b25ef0a5
Author:    iklam <ilam3388 at gmail.com>
Date:      2024-03-15 15:58:42 +0000
URL:       https://git.openjdk.org/leyden/commit/b25ef0a562fd1d816edf2c2eea66fe825965e0f7

Added "make mainline_vs_premain" to get simple comparisons of pet clinic

! test/hotspot/jtreg/premain/spring-petclinic/Makefile