NPE on dump shards

[bootstraponline]

Describe the bug

A clear and concise description of what the bug is.

NPE when running --dump-shards in the flank repo.

To Reproduce

Steps to reproduce the behavior:

0. cd ./test_runner in the Flank repo
1. Run flank android run --dump-shards
2. See error

java.lang.NullPointerException: File(this).parent must not be null
	at ftl.run.DumpShardsKt.createDirectories(DumpShards.kt:74)
	at ftl.run.DumpShardsKt.saveShardChunks(DumpShards.kt:67)
	at ftl.run.DumpShardsKt.dumpShards(DumpShards.kt:29)
	at ftl.run.DumpShardsKt$dumpShards$1.invokeSuspend(DumpShards.kt)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
	at kotlinx.coroutines.internal.ScopeCoroutine.afterResume(Scopes.kt:32)
	at kotlinx.coroutines.AbstractCoroutine.resumeWith(AbstractCoroutine.kt:113)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:46)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:106)
	at kotlinx.coroutines.EventLoopImplBase.processNextEvent(EventLoop.common.kt:274)
	at kotlinx.coroutines.BlockingCoroutine.joinBlocking(Builders.kt:84)
	at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking(Builders.kt:59)
	at kotlinx.coroutines.BuildersKt.runBlocking(Unknown Source)
	at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking$default(Builders.kt:38)
	at kotlinx.coroutines.BuildersKt.runBlocking$default(Unknown Source)
	at ftl.cli.firebase.test.android.AndroidRunCommand.run(AndroidRunCommand.kt:71)
	at picocli.CommandLine.executeUserObject(CommandLine.java:1939)
	at picocli.CommandLine.access$1300(CommandLine.java:145)
	at picocli.CommandLine$RunLast.executeUserObjectOfLastSubcommandWithSameParent(CommandLine.java:2352)
	at picocli.CommandLine$RunLast.handle(CommandLine.java:2346)
	at picocli.CommandLine$RunLast.handle(CommandLine.java:2311)
	at picocli.CommandLine$AbstractParseResultHandler.execute(CommandLine.java:2179)
	at picocli.CommandLine.execute(CommandLine.java:2078)
	at ftl.Main$Companion$main$1.invoke(Main.kt:59)
	at ftl.Main$Companion$main$1.invoke(Main.kt:51)
	at ftl.run.exception.ExceptionHandlerKt.withGlobalExceptionHandling(ExceptionHandler.kt:21)
	at ftl.run.exception.ExceptionHandlerKt.withGlobalExceptionHandling(ExceptionHandler.kt:12)
	at ftl.Main$Companion.main(Main.kt:54)
	at ftl.Main.main(Main.kt)

Expected behavior

A clear and concise description of what you expected to happen.

Expected not to crash.

Details (please complete the following information):

Have you tested on the latest Flank snapshot?

Post the output of flank --version.

$ flank --version
version: local_snapshot
revision: a007f6c7fbe67f138eb41c9d0dd812b8230acabb
session id: a84d5a7a-6ebf-473d-a308-f5693e141ff3

Additional context

Add any other context about the problem here.

[pawelpasterz]

#1557
https://github.com/Flank/flank/pull/1557/files#diff-fe7cc4b5e4bb0f11c6d4fd904bb1288ad61f3586eb258cf0916de6d8a86205a6R74

[pawelpasterz]

Within fix for this issue, we should also add IT for dump shards. It should verify created json

[zuziaka]

Marking as P0 as it's a release blocker.