Deflake LoopTest.WaitOneBlocking by increasing timeout.

[ScottTodd]

This test case has failed a few times on macos_x86, and possibly on other platforms too. I suspect the OS isn't scheduling the test threads soon enough - there's only a 150 millisecond window between the event set on a worker thread and iree_loop_wait_one's timeout on the main thread:

main thread                worker thread
-----------                -------------
test start
spin up thread   ------>   wait 50ms
wait 200ms                 ...
...              <------   set event
timeout if event not set

Sample logs:

• https://github.com/iree-org/iree/actions/runs/9214985535/job/25352380335#step:10:1578
• https://github.com/iree-org/iree/actions/runs/9882364677/job/27295096340?pr=17856#step:9:43

[ RUN      ] LoopTest.WaitOneBlocking
iree/runtime/src/iree/base/loop_test.h:612: Failure
Value of: status
Expected: error code OK
  Actual: 0x4, whose error code is DEADLINE_EXCEEDED: DEADLINE_EXCEEDED

[  FAILED  ] LoopTest.WaitOneBlocking (200 ms)

We could also use an infinite timeout.

[benvanik]

nice!

[ScottTodd]

https://github.com/iree-org/iree/actions/runs/9883115135/job/27297254957#step:9:95 oh, should also change WaitAllBlocking (and maybe other test cases? I'll check)

[ RUN      ] LoopTest.WaitAllBlocking
iree/runtime/src/iree/base/loop_test.h:962: Failure
Value of: status
Expected: error code OK
  Actual: 0x4, whose error code is DEADLINE_EXCEEDED: DEADLINE_EXCEEDED

[  FAILED  ] LoopTest.WaitAllBlocking (202 ms)
[----------] 25 tests from LoopTest (893 ms total)

[----------] 1 test from LoopInlineTest
[ RUN      ] LoopInlineTest.ExternalStorage
[       OK ] LoopInlineTest.ExternalStorage (0 ms)
[----------] 1 test from LoopInlineTest (0 ms total)

[----------] Global test environment tear-down
[==========] 26 tests from 2 test suites ran. (893 ms total)
[  PASSED  ] 25 tests.
[  FAILED  ] 1 test, listed below:
[  FAILED  ] LoopTest.WaitAllBlocking

 1 FAILED TEST