8014489: tests/gc/arguments/Test(Serial|CMS|Parallel|G1)HeapSizeFlags jtreg tests invoke wrong class
Summary: Some jtreg tests reference unknown classes in the @run and @build lines. This change fixes them.
Reviewed-by: stefank, ehelin

Summary: The patch for 8006088 misses regression tests after a merge error, this CR provides them.
Reviewed-by: jwilhelm, tamao, jmasa