Revert "[infra] Try to handle failing to restore the crash resource limit instead."

This reverts commit 225682f.
The reverted commit is reviewed at
https://dart-review.googlesource.com/c/sdk/+/127164

An added check for None from this change is kept, and not reverted.

Revert "[infra] Temporarily disable exception for invalid core pattern"

This reverts commit 1a41670.
The reverted commit is reviewed at
https://dart-review.googlesource.com/c/sdk/+/127163

These commits were temporary workarounds for a change in swarming
that changed the core_pattern for linux core dumps.
That change is reverted, and the workarounds should be removed.
See issue https://bugs.chromium.org/p/chromium/issues/detail?id=1030546

Closes: #39662
Bug: https://bugs.chromium.org/p/chromium/issues/detail?id=1030546
Change-Id: Idf41549f02df7918e9fb0704b0f4dd7cad6ddcf3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/127461
Reviewed-by: Jonas Termansen <sortie@google.com>

Author: whesse

tools/utils.py

@@ -749,7 +749,6 @@ def CheckLinuxCoreDumpPattern(fatal=False):
             raise Exception(message)
         else:
             print(message)
-            return True  # TODO(39662): Remove once the core_pattern is fixed
             return False
     return True