[test_runner] First batch test after compiler launch gets more timeout

The first test being compiled on a batch compiler pays for the cost of
the batch compiler startup, meaning it is more likely to time out, e.g.
see https://github.com/dart-lang/sdk/issues/53672.
E.g via
`tools/test.py '--progress=status' --report --time --write-results --write-logs --clean-exit -ncfe-strong-linux service/next_...`

I get output like this:
```
0:00:37.713771 - fasta - fasta-none release_x64/service/next_through_simple_linear_test/service
0:00:37.682524 - fasta - fasta-none release_x64/service/next_through_for_loop_with_break_and_continue_test/dds
0:00:36.805734 - fasta - fasta-none release_x64/service/next_through_create_list_and_map_test/service
0:00:36.589329 - fasta - fasta-none release_x64/service/next_through_simple_linear_2_test/dds
0:00:36.586428 - fasta - fasta-none release_x64/service/next_through_simple_linear_2_test/service
0:00:36.518832 - fasta - fasta-none release_x64/service/next_through_for_each_loop_test/dds
0:00:36.407107 - fasta - fasta-none release_x64/service/next_through_create_list_and_map_test/dds
0:00:36.259945 - fasta - fasta-none release_x64/service/next_through_for_each_loop_test/service
0:00:36.211573 - fasta - fasta-none release_x64/service/next_through_call_on_field_in_class_test/service
0:00:36.189456 - fasta - fasta-none release_x64/service/next_through_call_on_field_in_class_test/dds
0:00:35.974007 - fasta - fasta-none release_x64/service/next_through_for_loop_with_break_and_continue_test/service
0:00:35.921138 - fasta - fasta-none release_x64/service/next_through_simple_linear_test/dds
0:00:09.690812 - fasta - fasta-none release_x64/service/next_through_multi_catch_test/service
0:00:09.562068 - fasta - fasta-none release_x64/service/async_next_test/service
0:00:09.530882 - fasta - fasta-none release_x64/service/next_through_operator_bracket_test/dds
0:00:09.407169 - fasta - fasta-none release_x64/service/next_through_function_expression_test/dds
0:00:09.366673 - fasta - fasta-none release_x64/service/next_through_multi_catch_test/dds
0:00:09.327895 - fasta - fasta-none release_x64/service/next_through_function_expression_test/service
0:00:09.303926 - fasta - fasta-none release_x64/service/next_through_await_for_test/service
0:00:09.236295 - fasta - fasta-none release_x64/service/next_through_simple_async_with_returns_test/dds
```

where the first 12 (the really slow ones) each is the first test being
run on that particular batch compiler, where they both pay for the
startup cost of the batch compiler (~12 seconds on my machine when
launching 12 simultaneously which is the default on my machine -- it's
probably more on the bots) and for the jit not having warmed up yet:
E.g. the first test compiles in ~22 seconds, the second in ~9 seconds,
the third in ~6 seconds on my machine (again with 12 simultaneous runs).

To make it less likely that the first compile times out this CL adds
some extra time allowance for the first run after the bulk compiler is
started. For now it's 30 seconds, but it can be adjusted if needed.

Longer term we should probably start a batch compilation test by
aot-compilng the batch compiler (which, at least currently,
doesn't support asserts
(https://github.com/dart-lang/sdk/issues/53343)
which is unfortunate).
I'll leave that for a future CL.

Bug: https://github.com/dart-lang/sdk/issues/53672

Change-Id: Id3427223c46c1e7a34b401097a3f7d5f1321ad93
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/332220
Commit-Queue: Jens Johansen <jensj@google.com>
Reviewed-by: William Hesse <whesse@google.com>