ModGC

Improve syntax style consistency in shape.c and shape.h #338

Job	Run time
check (default, macos-latest)	8m 7s
check (default, ubuntu-latest)	6m 42s
check (mmtk, release, macos-latest)	8m 4s
check (mmtk, release, ubuntu-latest)	8m 8s
	31m 1s

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