Increase gradle memory in integration tests

[dimas-b]

To fix OOM errors like this:

 > Task :iceberg:iceberg-spark:iceberg-spark-3.3_2.12:compileTestJava FAILED
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
compiler message file broken: key=compiler.misc.msg.bug arguments=11.0.17, {1}, {2}, {3}, {4}, {5}, {6}, {7}
java.lang.OutOfMemoryError: Java heap space

from #5647 (comment)

[codecov]

Codecov Report

Base: 79.34% // Head: 79.34% // No change to project coverage 👍

Coverage data is based on head (c648898) compared to base (da8c050).
Patch has no changes to coverable lines.

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #5654   +/-   ##
=========================================
  Coverage     79.34%   79.34%           
  Complexity     3717     3717           
=========================================
  Files           535      535           
  Lines         16479    16479           
  Branches       1613     1613           
=========================================
  Hits          13075    13075           
  Misses         2783     2783           
  Partials        621      621           

Flag	Coverage Δ
java	78.80% <ø> (ø)
javascript	82.91% <ø> (ø)
python	83.91% <ø> (ø)

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