Fix ImageDataUtil.copyPixels crash on Hashlink #1380

Job	Run time
android	25m 29s
docs	28s
air-samples (4.0.5)	3m 13s
air-samples (4.1.5)	3m 12s
flash-samples	36s
html5-samples	1m 34s
ios	23m 27s
air-samples (4.2.5)	3m 12s
linux	14m 23s
air-samples (4.3.1)	2m 46s
macos	30m 51s
windows	14m 6s
package-haxelib	1m 32s
hashlinkc-samples (windows-latest)	1m 48s
hashlink-samples (windows-latest)	47s
hashlinkc-samples (ubuntu-20.04)	1m 30s
hashlink-samples (ubuntu-20.04)	25s
hashlinkc-samples (macos-13)	2m 1s
hashlink-samples (macos-13)	42s
neko-samples (3.4.7, windows-latest)	53s
neko-samples (3.4.7, ubuntu-20.04)	15s
neko-samples (3.4.7, macos-13)	45s
neko-samples (4.2.5, windows-latest)	1m 19s
neko-samples (4.2.5, ubuntu-20.04)	24s
neko-samples (4.2.5, macos-13)	1m 3s
notify	0s
	2h 16m 41s

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