[lworld] RFR: 8377353: [lworld] compiler/valhalla/inlinetypes/TestStressReturnBuffering.java OOMs with ZGC and AOT class linking with --enable-preview

[Damon Fenacci]

# Issue

`compiler/valhalla/inlinetypes/TestStressReturnBuffering.java` fails when run with `-XX:+AOTClassLinking -XX:+UseZGC --enable-preview`

# Cause

The test limits the heap size using `-Xmx6m`, which is not always enough to run it with ZGC and AOTClassLinking.

# Fix

Raising the limit a little to `-Xmx10m` fixes the issue (while still forcing frequent garbage collections).

# Testing

Tier 1-3+
Failing test before and after

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Commit messages:
 - JDK-8377353: [lworld] compiler/valhalla/inlinetypes/TestStressReturnBuffering.java OOMs with ZGC and AOT class linking with --enable-preview

Changes: https://git.openjdk.org/valhalla/pull/2093/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=2093&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8377353
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/valhalla/pull/2093.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/2093/head:pull/2093

PR: https://git.openjdk.org/valhalla/pull/2093