CI: remove reruns on all failures.

This is covering up real bugs; we need to fix CI instead.

From https://pypi.org/project/pytest-rerunfailures/#re-run-all-failures:

```
To re-run all test failures, use the --reruns command line option with the maximum number of times you’d like the tests to run:

$ pytest --reruns 5
```

Signed-off-by: Rusty Russell <[email protected]>

Author: rustyrussell

.github/workflows/ci.yaml

@@ -16,7 +16,7 @@ env:
   RUST_PROFILE: release
   SLOW_MACHINE: 1
   CI_SERVER_URL: "http://35.239.136.52:3170"
-  GLOBAL_PYTEST_OPTS: "--reruns=10 -vvv"
+  GLOBAL_PYTEST_OPTS: "-vvv"
 
 jobs:
   prebuild:
@@ -431,7 +431,7 @@ jobs:
     env:
       RUST_PROFILE: release # Has to match the one in the compile step
       CFG: compile-gcc
-      PYTEST_OPTS: --test-group-random-seed=42 --timeout=1800 --durations=10 --reruns=10
+      PYTEST_OPTS: --test-group-random-seed=42 --timeout=1800 --durations=10
     needs:
       - compile
     strategy:
@@ -502,7 +502,7 @@ jobs:
       RUST_PROFILE: release
       SLOW_MACHINE: 1
       TEST_DEBUG: 1
-      PYTEST_OPTS: --test-group-random-seed=42 --timeout=1800 --durations=10 --reruns=10
+      PYTEST_OPTS: --test-group-random-seed=42 --timeout=1800 --durations=10
     needs:
       - compile
     strategy: