`=no` values for sanitizer configure options still enable sanitizer flags

Bug report

Bug description:

Summary

Passing no to a sanitizer option is reported as disabled, but the option's action still adds sanitizer compiler and linker flags. For AddressSanitizer, it also disables pymalloc.

Reproduction

mkdir build
cd build

../configure --with-address-sanitizer=no
grep -E '^(BASECFLAGS|LDFLAGS)=' Makefile
grep WITH_PYMALLOC pyconfig.h

Actual Behavior

Configure reports:

checking for --with-address-sanitizer... no
checking for --with-pymalloc... no

Despite that output, the AddressSanitizer action adds -fsanitize=address to BASECFLAGS and LDFLAGS, and sets with_pymalloc=no.

Expected Behavior

--with-address-sanitizer=no should not enable AddressSanitizer flags and should not change the pymalloc setting. It should have the same result as omitting the option or using the corresponding --without-... form.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-157355

Start by running the provided configure reproduction on the CPython main branch and inspect the sanitizer configure-option handling that adds BASECFLAGS, LDFLAGS, and changes with_pymalloc. Done means passing --with-address-sanitizer=no leaves sanitizer flags and the pymalloc setting unchanged, matching an omitted option or corresponding --without form.