test(android): Add Jetpack Macrobenchmark for SDK init performance (JAVA-604)

[runningcode]

📜 Description

Adds sentry-uitest-android-macrobenchmark, a Jetpack Macrobenchmark module that measures cold start of sentry-samples-android on a connected device. It reports timeToInitialDisplay (StartupTimingMetric) per iteration, taken from framework trace events — no trace markers needed in the SDK or the app. Each iteration's perfetto trace is saved for deeper analysis.

Details:

• CompilationMode.Full() pins ART AOT compilation so dexopt state can't drift between runs; StartupMode.COLD force-stops (no pm clear) so app data persists.
• Iterations are capped at 12 — back-to-back cold starts thermally throttle an unlocked-clock device after ~14 iterations.
• The sample app gains a <profileable android:shell="true"/> manifest flag (required to profile its non-debuggable release build) — its only change.
• The module's debug variant is disabled; the benchmark build type pairs the debuggable test APK with the app's release build via matchingFallbacks.
• Requires androidx.benchmark 1.4.1: 1.3.4 fails with "Unable to confirm activity launch completion" on Android 16 (API 36).
• Not run in CI; see the module README for device hygiene and interleaved A/B methodology.

💡 Motivation and Context

We currently rely on ad-hoc btrace/perfetto captures to measure Android SDK init cost. A Macrobenchmark gives a stable, reproducible, on-device measurement to validate init-time changes, and could be wired into CI later.

Closes #5679 (JAVA-604)

💚 How did you test it?

Ran connectedBenchmarkAndroidTest on a Galaxy A55 (Android 16): TTID median 514.5 ms (min 496.2, max 585.4, stdev 24.3, n=12), with no thermal degradation across iterations.

📝 Checklist

• I added GH Issue ID & Linear ID
• I added tests to verify the changes.
• No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
• I updated the docs if needed.
• I updated the wizard if needed.
• Review from the native team if needed.
• No breaking change or entry added to the changelog.
• No breaking change for hybrid SDKs or communicated to hybrid SDKs.

🔮 Next steps

• Use this to A/B upcoming SDK init-time changes (interleaved rounds, see README).
• Potentially wire into CI with a device farm later.

#skip-changelog

🤖 Generated with Claude Code

[linear-code]

JAVA-604

[sentry]

📲 Install Builds

Android

🔗 App Name	App ID	Version	Configuration
SDK Size	io.sentry.tests.size	8.47.0 (1)	release

⚙️ sentry-android Build Distribution Settings

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	346.28 ms	427.00 ms	80.72 ms
Size	0 B	0 B	0 B

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
abfcc92	304.04 ms	370.33 ms	66.29 ms
4e3e79d	365.83 ms	477.62 ms	111.79 ms
d8912da	329.94 ms	389.68 ms	59.74 ms
d15471f	294.13 ms	399.49 ms	105.36 ms
abf451a	332.82 ms	403.67 ms	70.85 ms
604a261	380.65 ms	451.27 ms	70.62 ms
806307f	357.85 ms	424.64 ms	66.79 ms
22f4345	307.87 ms	354.51 ms	46.64 ms
d217708	375.27 ms	415.68 ms	40.41 ms
c3ee041	310.64 ms	361.90 ms	51.26 ms

App size

Revision	Plain	With Sentry	Diff
abfcc92	1.58 MiB	2.13 MiB	557.31 KiB
4e3e79d	0 B	0 B	0 B
d8912da	0 B	0 B	0 B
d15471f	1.58 MiB	2.13 MiB	559.54 KiB
abf451a	1.58 MiB	2.20 MiB	635.29 KiB
604a261	1.58 MiB	2.10 MiB	533.42 KiB
806307f	1.58 MiB	2.10 MiB	533.42 KiB
22f4345	1.58 MiB	2.29 MiB	719.83 KiB
d217708	1.58 MiB	2.10 MiB	532.97 KiB
c3ee041	0 B	0 B	0 B

Previous results on branch: no/java-604-add-jetpack-macrobenchmark

Startup times

Revision	Plain	With Sentry	Diff
ccccf4a	311.09 ms	358.70 ms	47.61 ms

App size

Revision	Plain	With Sentry	Diff
ccccf4a	0 B	0 B	0 B

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