[K/N] Use LLD 12.0.1 for MinGW targets

Clang-produced and GCC-produced binaries might be ABI-incompatible on
MinGW. Explanation on GitHub: msys2/MINGW-packages/issues/6855#issuecomment-680859662.
TL;DR: GCC-generated sections are 16-byte-padded, while Clang ones are
not. It causes problems during merge of COMDAT sections.
I observed the problem during compilation of runtime tests, but it is
possible that the problem could affect main compilation pipeline as well.
https://reviews.llvm.org/D86659 (which landed in LLVM 12) fixes
the problem. So we have another motivation for switching to LLD besides
https://youtrack.jetbrains.com/issue/KT-47605.

The only known downside is unsupported defsym which causes slight binary
size increase. I think it is doable.

kotlin-native/backend.native/cli.bc/src/org/jetbrains/kotlin/cli/bc/K2Native.kt

@@ -318,15 +318,6 @@ class K2Native : CLICompiler<K2NativeCompilerArguments>() {
                     configuration.report(ERROR, "-Xgc-aggressive is only supported for -memory-model experimental")
                 }
                 put(GARBAGE_COLLECTOR_AGRESSIVE, arguments.gcAggressive)
-                put(CHECK_LLD_COMPATIBILITY, when (val it = arguments.checkLldCompatibility) {
-                    "enable" -> true
-                    "disable" -> false
-                    null -> true
-                    else -> {
-                        configuration.report(ERROR, "Unsupported '-Xcheck-compatibility-with-lld' value: $it. Possible values are 'enable'/'disable'")
-                        true
-                    }
-                })
                 put(RUNTIME_ASSERTS_MODE, when (arguments.runtimeAssertsMode) {
                     "ignore" -> RuntimeAssertsMode.IGNORE
                     "log" -> RuntimeAssertsMode.LOG

kotlin-native/backend.native/cli.bc/src/org/jetbrains/kotlin/cli/bc/K2NativeCompilerArguments.kt

@@ -317,13 +317,6 @@ class K2NativeCompilerArguments : CommonCompilerArguments() {
     @Argument(value = "-Xir-property-lazy-initialization", description = "Initialize top level properties lazily per file")
     var propertyLazyInitialization: Boolean = false
 
-    @Argument(
-            value = "-Xcheck-compatibility-with-lld",
-            valueDescription = "{disable|enable}",
-            description = "Check that linker flags are compatible with LLD."
-    )
-    var checkLldCompatibility: String? = null
-
     @Argument(value="-Xruntime-asserts-mode", valueDescription = "<mode>", description = "Enable asserts in runtime. Possible values: 'ignore', 'log', 'panic'")
     var runtimeAssertsMode: String? = "ignore"