Add goblint_cil_pulledup attribute to static local variables pulled up to global scope

[Copilot]

CIL promotes static local variables to globals, making them indistinguishable from true globals. This adds a goblint_cil_pulledup attribute to such variables so consumers (e.g. goblint analyzer) can identify them.

Changes

• src/frontc/cabs2cil.ml: In the sto = Static && !makeStaticGlobal branch where local statics are promoted to globals, stamp the resulting varinfo with Attr("goblint_cil_pulledup", []) — mirrors the existing goblint_cil_nested pattern.

Example

Given:

void foo() {
    static int counter = 0;  // pulled up to global scope by CIL
    counter++;
}

The resulting global varinfo for counter will carry __attribute__((goblint_cil_pulledup)), allowing downstream tools to distinguish it from a genuinely file-scoped global.