Reinstate DevModeTestUtil to avoid breaking other projects that depend on it #32229

Job	Run time
CI Sanity Check	31s
Initial JDK 11 Build	32m 20s
Attach pull request number	4s
Calculate Test Jobs	12s
Gradle Tests - JDK 11	38m 15s
Gradle Tests - JDK 11 Windows	1h 20m 40s
Quickstarts Compilation - JDK 17	10m 59s
Maven Tests - JDK 11	53m 5s
Maven Tests - JDK 11 Windows	1h 15m 52s
Devtools Tests - JDK ${{ matrix.java.name }}	0s
JVM Tests - JDK 11	21m 48s
JVM Tests - JDK 17	28m 8s
JVM Tests - JDK 20	23m 40s
JVM Tests - JDK 17 Windows	20m 59s
Native Tests - Misc1	6m 19s
Native Tests - Misc2	8m 29s
Native Tests - Misc4	41m 22s
Virtual Thread Support Tests Native - ${{ matrix.category }}	0s
MicroProfile TCKs Tests	0s
Build report	0s
	7h 22m 43s

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