Remove //@ ignore-windows-gnu from tests that need the profiler

The profiler runtime is no longer built in mingw test jobs, so these tests
should naturally be skipped by `//@ needs-profiler-support`.

src/tools/compiletest/src/header.rs

@@ -1023,9 +1023,6 @@ fn iter_header(
     if mode == Mode::CoverageRun {
         let extra_directives: &[&str] = &[
             "needs-profiler-support",
-            // FIXME(mati865): MinGW GCC miscompiles compiler-rt profiling library but with Clang it works
-            // properly. Since we only have GCC on the CI ignore the test for now.
-            "ignore-windows-gnu",
             // FIXME(pietroalbini): this test currently does not work on cross-compiled
             // targets because remote-test is not capable of sending back the *.profraw
             // files generated by the LLVM instrumentation.