Test runtime/7020373/Test7020373.sh expects that if there will not be enough free memory than java will crash and crash message will contains something like:
# There is insufficient memory for the Java Runtime Environment to continue.
# Native memory allocation (malloc) failed to allocate 5243484320 bytes for Chunk::new

It is true for JDK 6.0, but JDK 5.0 in the same situation only throws next exception:
Exception in thread "main" java.lang.OutOfMemoryError: requested 948517024 bytes for Chunk::new. Out of swap space?

See log example:
http://vice.russia.sun.com/results/1.5.0_36/b01/vm/win2008r2-x64-64_hs/workDir/runtime/7020373/Test7020373.jtr

Test fails intermittently with both JDK 1.5.0_36 b01 and JDK 1.5.0 FCS.
Issue reproduced in case when there is in fact not much free memory. I found that sometimes tests that was started before Test7020373.sh and failed may not be interrupted and memory used by them not freed. In this situation OOME will be throwed by the test.

Issue seems to be related to CR 7053586, but since MR targeted to JDK 5.0 was closed I'm opening new CR.