[BUG] remove --gc-sections from debug cmake variant with new toolchain file

### Description

https://github.com/android/ndk/issues/1813 wasn't able to be fixed for the new toolchain file because CMake doesn't offer us that level of control. We need to get CMake fixed to allow us to fix this for that configuration.

### Affected versions

r25, Canary

### Canary version

_No response_

### Host OS

Linux, Mac, Windows

### Host OS version

any

### Affected ABIs

armeabi-v7a, arm64-v8a, x86, x86_64

### Build system

CMake

### Other build system

_No response_

### minSdkVersion

any

### Device API level

_No response_

Start by reading this issue alongside android/ndk#1813 and reproducing the debug CMake variant with the new toolchain file across the listed ABIs. Investigate how CMake applies --gc-sections in that configuration; the work is done when the flag can be removed from the debug variant without regressing the supported hosts or ABIs.

Written by the indexing model from the issue text.