[coverage] crash with ExprWithCleanups in `if constexpr`

[hanickadot]

Clang main and 18 crashes with this code: (-fprofile-instr-generate -fcoverage-mapping -std=c++17)

struct false_value {
	constexpr operator bool() {
		return false;
	}
};

void foo()
{
	if constexpr (false_value{}) { };
}

https://godbolt.org/z/833ej19rP

It's a bug in my recent change #78033 ... writing patch now, this is so it's visible.

[llvmbot]

@llvm/issue-subscribers-clang-codegen

Author: Hana Dusíková (hanickadot)

Clang `main` and `18` crashes with this code: (`-fprofile-instr-generate -fcoverage-mapping -std=c++17`)

struct false_value {
	constexpr operator bool() {
		return false;
	}
};

void foo()
{
	if constexpr (false_value{}) { };
}

https://godbolt.org/z/833ej19rP

It's a bug in my recent change #78033 ... writing patch now, this is so it's visible.

[hanickadot]

/cherry-pick bfc6eaa