[K/N] Disable mimalloc for MinGW on Linux and Windows

There is a case-sensitivity problem when cross-compiling to MinGW.
https://github.com/microsoft/mimalloc/commit/71ac98a fixes the problem,
but it is not included into our current version of mimalloc.

kotlin-native/shared/src/main/kotlin/org/jetbrains/kotlin/konan/target/KonanTargetExtenstions.kt

@@ -14,8 +14,8 @@ fun KonanTarget.supportsCodeCoverage(): Boolean =
 fun KonanTarget.supportsMimallocAllocator(): Boolean =
      when(this) {
         is KonanTarget.LINUX_X64 -> true
-        is KonanTarget.MINGW_X86 -> true
-        is KonanTarget.MINGW_X64 -> true
+        is KonanTarget.MINGW_X86 -> HostManager.hostIsMingw
+        is KonanTarget.MINGW_X64 -> HostManager.hostIsMingw
         is KonanTarget.MACOS_X64 -> true
         is KonanTarget.LINUX_ARM64 -> true
         is KonanTarget.LINUX_ARM32_HFP -> true