When we subsequently execute two tests in different folders (but in the same package and with the same name), jtreg does not build the second test but executes the already built first test with the command line of the second test:

For example:
jtreg [...] closed/test/hotspot/jtreg/compiler/c1/TestPinnedIntrinsics.java
jtreg [...] open/test/hotspot/jtreg/compiler/c1/TestPinnedIntrinsics.java

See JDK-8195648 for more details.