refactor(test): extract shared DB provisioning helper

[VuMartin]

What changes were proposed in this PR?

Extract the shared test database provisioning logic from TestUtils.initiateTexeraDBForTestCases and MockTexeraDB.initializeDBAndReplaceDSLContext into a reusable MockTexeraDB.createTestDatabase helper.

The helper centralizes the creation of an isolated test database and execution of the cached DDL script, while preserving the existing database naming and connection/resource lifecycle behavior.

Any related issues, documentation, discussions?

Closes #6421

How was this PR tested?

• Ran DAO / test successfully.
• Ran PauseSpec successfully.
• Ran ReconfigurationSpec successfully.
• Ran DataProcessingSpec successfully.

Was this PR authored or co-authored using generative AI tooling?

Generated-by: ChatGPT (5.5 mini)

[github-actions]

Automated Reviewer Suggestions

Based on the git blame history of the changed files, we recommend the following reviewers:

• Contributors with relevant context: @eugenegujing, @Neilk1021
  You can notify them by mentioning @eugenegujing, @Neilk1021 in a comment.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.94%. Comparing base (bda3400) to head (a064e1d).

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #8457      +/-   ##
============================================
- Coverage     93.94%   93.94%   -0.01%     
+ Complexity     4826     4825       -1     
============================================
  Files          1209     1209              
  Lines         49705    49705              
  Branches       6074     6074              
============================================
- Hits          46694    46693       -1     
  Misses         1522     1522              
- Partials       1489     1490       +1     

Flag	Coverage Δ		*Carryforward flag
access-control-service	80.18% <ø> (ø)
agent-service	99.32% <ø> (ø)		Carriedforward from bda3400
amber	89.91% <ø> (-0.01%)	⬇️
computing-unit-managing-service	75.05% <ø> (ø)
config-service	87.12% <ø> (ø)
file-service	83.65% <ø> (ø)
frontend	96.77% <ø> (ø)		Carriedforward from bda3400
notebook-migration-service	83.73% <ø> (ø)
pyamber	98.47% <ø> (ø)		Carriedforward from bda3400
workflow-compiling-service	77.19% <ø> (ø)

*This pull request uses carry forward flags. Click here to find out more.

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[github-actions]

⚠️ Benchmark changes need a look

🟢 2 better · 🔴 9 worse · ⚪ 4 noise (<±5%) · 0 without baseline

Compared against main bda3400 benchmarked on this same runner, so the delta is largely free of cross-runner hardware noise. The "7d avg" column still reflects the gh-pages dashboard. Treat <±5% as noise unless repeated.

Dashboard · Run

	config	throughput	MB/s	latency	max Δ latest / 7d
🔴	bs=10 sw=10 sl=64	386	0.235	24,423/40,554/40,554 us	🔴 +40.6% / 🔴 +154.2%
🔴	bs=100 sw=10 sl=64	883	0.539	107,061/166,195/166,195 us	🔴 +40.3% / 🔴 +53.3%
🟢	bs=1000 sw=10 sl=64	1,113	0.68	894,810/962,215/962,215 us	🟢 -7.1% / 🟢 +10.3%

Baseline details

Latest main bda3400 from same runner

config	metric	PR	latest main	7d avg	Δ latest	Δ 7d
bs=10 sw=10 sl=64	throughput	386 tuples/sec	466 tuples/sec	758.07 tuples/sec	-17.2%	-49.1%
bs=10 sw=10 sl=64	MB/s	0.235 MB/s	0.284 MB/s	0.463 MB/s	-17.3%	-49.2%
bs=10 sw=10 sl=64	p50	24,423 us	21,952 us	12,892 us	+11.3%	+89.4%
bs=10 sw=10 sl=64	p95	40,554 us	28,842 us	15,953 us	+40.6%	+154.2%
bs=10 sw=10 sl=64	p99	40,554 us	28,842 us	19,452 us	+40.6%	+108.5%
bs=100 sw=10 sl=64	throughput	883 tuples/sec	980 tuples/sec	985.38 tuples/sec	-9.9%	-10.4%
bs=100 sw=10 sl=64	MB/s	0.539 MB/s	0.598 MB/s	0.601 MB/s	-9.9%	-10.4%
bs=100 sw=10 sl=64	p50	107,061 us	103,131 us	101,292 us	+3.8%	+5.7%
bs=100 sw=10 sl=64	p95	166,195 us	118,464 us	108,395 us	+40.3%	+53.3%
bs=100 sw=10 sl=64	p99	166,195 us	118,464 us	119,793 us	+40.3%	+38.7%
bs=1000 sw=10 sl=64	throughput	1,113 tuples/sec	1,092 tuples/sec	1,010 tuples/sec	+1.9%	+10.2%
bs=1000 sw=10 sl=64	MB/s	0.68 MB/s	0.667 MB/s	0.616 MB/s	+1.9%	+10.3%
bs=1000 sw=10 sl=64	p50	894,810 us	909,986 us	997,720 us	-1.7%	-10.3%
bs=1000 sw=10 sl=64	p95	962,215 us	1,035,210 us	1,040,349 us	-7.1%	-7.5%
bs=1000 sw=10 sl=64	p99	962,215 us	1,035,210 us	1,070,423 us	-7.1%	-10.1%

Raw CSV

config_idx,batch_size,schema_width,string_len,num_batches,total_ms,total_tuples,total_bytes,tuples_per_sec,mb_per_sec,lat_p50_us,lat_p95_us,lat_p99_us
0,10,10,64,20,518.52,200,128000,386,0.235,24422.70,40554.44,40554.44
1,100,10,64,20,2263.83,2000,1280000,883,0.539,107061.34,166194.82,166194.82
2,1000,10,64,20,17963.15,20000,12800000,1113,0.680,894810.35,962215.11,962215.11