RFR: 8321812: Update GC tests to use execute[Limited]TestJava [v6]

[Axel Boldt-Christmas]

On Wed, 3 Jan 2024 13:32:18 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

>> A lot of our tests use a multi-step recipe to spawn and wait for a process. Here's an example
>> 
>>     ProcessBuilder pb = ProcessTools.createTestJavaProcessBuilder(
>>          "-XX:-UseTLAB",
>>          "-XX:+UnlockDiagnosticVMOptions",
>>          "-XX:+VerifyDuringStartup",
>>          "-Xlog:gc+verify=debug",
>>          "-version");
>>     OutputAnalyzer output = new OutputAnalyzer(pb.start());
>>     ... do something with output and wait for the process to complete ...
>> 
>> 
>> These are the steps involved:
>> 
>> 1) Create a `ProcessBuilder`
>> 2) Call `ProcessBuilder::start`
>> 3) Create an `OutputAnalyzer`
>> 4) Perform an operation that finally waits for the process to, at least partially, complete (OutputAnalyzer::getOutput, OutputAnalyzer::shouldHaveExitValue(), and more).
>> 
>> Almost all our tests could be converted to use a single call to `ProcessTools.executeTestJava` (or `executeLimitedTestJava`), which spawns the process, makes sure that it has fully completed, and then returns a filled-in OutputAnalyzer to the caller. The above example would become:
>> 
>> 
>>     OutputAnalyzer output = ProcessTools.executeTestJava(
>>          "-XX:-UseTLAB",
>>          "-XX:+UnlockDiagnosticVMOptions",
>>          "-XX:+VerifyDuringStartup",
>>          "-Xlog:gc+verify=debug",
>>          "-version");
>> 
>> 
>> I propose that we make this change in the GC tests, to make our code simpler and hopefully easier to read.
>> 
>> Note: There's a few changes to the throws statements because some ProcessTools APIs throws IOException while others throw Exception.
>> 
>> Testing: I've done testing on a similar set of changes, but I'm going to run the appropriate, final tests while this is being considered/reviewed.
>
> Stefan Karlsson has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - Update Shenandoah test
>  - Remove import from old version of the code

Marked as reviewed by aboldtch (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/17067#pullrequestreview-1803609295