build: disable -Og in debug mode to avoid coroutine asan breakage

Coroutines and asan don't mix well on aarch64. This was seen in
22f13e7ca3 (" Revert "Merge 'cql3: select_statement: coroutinize
indexed_table_select_statement::do_execute_base_query()' from Avi
Kivity"") where a routine coroutinization was reverted due to failures
on aarch64 debug mode.

In clang 15 this is even worse, the existing code starts failing.
However, if we disable optimization (-O0 rather than -Og), things
begin to work again. In fact we can reinstate the patch reverted
above even with clang 12.

Fix (or rather workaround) the problem by avoiding -Og on aarch64
debug mode. There's the lingering fear that release mode is
miscompiled too, but all the tests pass on clang 15 in release mode
so it appears related to asan.

Closes #11894

configure.py

@@ -289,7 +289,8 @@ modes = {
         'cxxflags': '-DDEBUG -DSANITIZE -DDEBUG_LSA_SANITIZER -DSCYLLA_ENABLE_ERROR_INJECTION',
         'cxx_ld_flags': '',
         'stack-usage-threshold': 1024*40,
-        'optimization-level': 'g',
+        # -fasan -Og breaks some coroutines on aarch64, use -O0 instead
+        'optimization-level': ('0' if platform.machine() == 'aarch64' else 'g'),
         'per_src_extra_cxxflags': {},
         'cmake_build_type': 'Debug',
         'can_have_debug_info': True,