[FIR] Disable not null checks on dynamics

It looks like K1 doesn't do them.
And it's not particularly bad because
in the ideal world we'd have dynamics
with variable upper bound so that
in `dynamic?.let { it }` `it` would
be `Nothing..Any` (smartcasting to
`Any` is not correct because `dynamic`
can be passed into anything, but `Any`
can not).

^KT-63071

compiler/testData/diagnostics/testsWithJsStdLib/dynamicTypes/extensionVals.fir.kt

@@ -12,7 +12,7 @@ fun test(d: dynamic) {
         d!!.<!DEBUG_INFO_DYNAMIC!>onAnyVal<!>
     }
     run {
-        d!!.<!UNRESOLVED_REFERENCE!>onAnyVal<!> = 1
+        d!!.<!DEBUG_INFO_DYNAMIC!>onAnyVal<!> = 1
     }
 
     d.<!DEBUG_INFO_DYNAMIC!>onNullableAnyVal<!> = 1

compiler/testData/diagnostics/testsWithJsStdLib/dynamicTypes/extensionVars.fir.kt

@@ -13,7 +13,7 @@ fun test(d: dynamic) {
 
     }
     run {
-        d!!.<!UNRESOLVED_REFERENCE!>onAnyVar<!> = 1
+        d!!.<!DEBUG_INFO_DYNAMIC!>onAnyVar<!> = 1
     }
 
     d.<!DEBUG_INFO_DYNAMIC!>onNullableAnyVar<!> = 1
@@ -22,7 +22,7 @@ fun test(d: dynamic) {
 
     d.<!DEBUG_INFO_DYNAMIC!>onDynamicVar<!> = 1
 
-    d?.<!DYNAMIC_RECEIVER_EXPECTED_BUT_WAS_NON_DYNAMIC!>onDynamicVar<!> = 1
+    d?.<!DEBUG_INFO_DYNAMIC!>onDynamicVar<!> = 1
 
     (d as String).onStringVar
     (d as Any).onAnyVar

compiler/testData/diagnostics/testsWithJsStdLib/dynamicTypes/extensions.fir.kt

@@ -14,7 +14,7 @@ fun test(d: dynamic) {
     d.<!DEBUG_INFO_DYNAMIC!>onString<!>()
 
     d.<!DEBUG_INFO_DYNAMIC!>onDynamic<!>()
-    d?.<!DYNAMIC_RECEIVER_EXPECTED_BUT_WAS_NON_DYNAMIC!>onDynamic<!>()
+    d?.<!DEBUG_INFO_DYNAMIC!>onDynamic<!>()
 
     (d as String).onString()
     (d as Any).onAny()