Fix flaky testExplainPlanQueryV2 by masking scientific-notation rule timings

[yashmayya]

Problem

OfflineClusterIntegrationTest#testExplainPlanQueryV2 is intermittently flaky. It compares the EXPLAIN output's "Rule Execution Times" section after masking each per-rule time with *, using the regex Time: \d+\.\d+.

Rule timings are rendered as durationNanos / 1_000_000.0 (a double) via Double.toString() in RuleTimingPlannerListener. When a rule runs fast enough (sub-microsecond, i.e. < 0.001 ms), Double.toString() switches to scientific notation such as 1.5E-4. The old regex matches only the 1.5 mantissa and leaves the exponent behind, producing Time:*E-4, which no longer matches the expected Time:*:

expected: Rule: AggregateProjectPullUpConstants -> Time:*
found:    Rule: AggregateProjectPullUpConstants -> Time:*E-4

The rule list itself is correct/unchanged — only the time-masking is wrong. This is a pre-existing flake, unrelated to any Calcite version.

Fix

Extend the masking regex to also strip an optional scientific-notation exponent, so both 1.5 and 1.5E-4 collapse to *:

Time: \d+\.\d+   ->   Time: \d+\.\d+(?:[eE][-+]?\d+)?

Applied to both occurrences in the test (the two responses asserted in the method).

Testing

./mvnw -pl pinot-integration-tests test -Dtest=OfflineClusterIntegrationTest#testExplainPlanQueryV2 -Dsurefire.failIfNoSpecifiedTests=false passes.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 64.40%. Comparing base (f6b930b) to head (c627060).
⚠️ Report is 49 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #18650      +/-   ##
============================================
- Coverage     64.45%   64.40%   -0.05%     
- Complexity     1282     1291       +9     
============================================
  Files          3352     3365      +13     
  Lines        207171   208066     +895     
  Branches      32348    32482     +134     
============================================
+ Hits         133534   134007     +473     
- Misses        62910    63283     +373     
- Partials      10727    10776      +49     

Flag	Coverage Δ
custom-integration1	100.00% <ø> (ø)
integration	100.00% <ø> (ø)
integration1	100.00% <ø> (ø)
integration2	0.00% <ø> (ø)
java-21	64.40% <ø> (-0.05%)	⬇️
temurin	64.40% <ø> (-0.05%)	⬇️
unittests	64.40% <ø> (-0.05%)	⬇️
unittests1	56.81% <ø> (+<0.01%)	⬆️
unittests2	37.13% <ø> (-0.03%)	⬇️

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