[unwinder] Clean up existing tests

Mostly a cleanup for x64.

Also enable two tests for Arm and Arm64 since they do not make use of
JSEntry frames.

Bug: v8:10833
Change-Id: Id6adadf582bdca0076460842ffe4ec856ca99393
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2381455
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69634}

test/cctest/cctest.status

@@ -473,8 +473,6 @@
 # Arm. They are disabled because the stack is not being set up the way it does
 # in the wild.
 ['arch == arm64 or arch == arm', {
-  'test-unwinder-code-pages/Unwind_BuiltinPCInMiddle_Success_CodePagesAPI': [SKIP],
-  'test-unwinder-code-pages/Unwind_BuiltinPCAtStart_Success_CodePagesAPI': [SKIP],
   'test-unwinder-code-pages/Unwind_CodeObjectPCInMiddle_Success_CodePagesAPI': [SKIP],
   'test-unwinder-code-pages/Unwind_JSEntryBeforeFrame_Fail_CodePagesAPI': [SKIP],
   'test-unwinder-code-pages/Unwind_OneJSFrame_Success_CodePagesAPI': [SKIP],