run-tests: Skip running emulated x86 binaries on aarch64, when targeting msvcrt

In this configuration, one test in crt-test.c fails, both for
i686 and x86_64, when running emulated on aarch64.

run-tests.sh

@@ -120,6 +120,16 @@ set_native() {
             NATIVE_ARMV7=1
             RUN_ARMV7=true
         fi
+
+        if [ -z "$IS_UCRT" ]; then
+            # If targeting msvcrt.dll, skip executing the x86 binaries
+            # emulated. They do run, but statically linked mingw math
+            # functions fail some tests, when running emulated; those functions
+            # rely on 80 bit long doubles actually having more precision than
+            # 64 bit doubles.
+            unset RUN_I686
+            unset RUN_X86_64
+        fi
         ;;
     esac
 }