Extract default language version settings for diagnostics tests

And override it in unsigned types diagnostics tests.
Remove InlineClasses feature directive from tests, because it's already
enabled in that language version.

compiler/testData/diagnostics/testsWithUnsignedTypes/allowedVarargsOfUnsignedTypes.kt

@@ -1,5 +1,3 @@
-// !LANGUAGE: +InlineClasses
-// !SKIP_METADATA_VERSION_CHECK
 // !DIAGNOSTICS: -UNUSED_PARAMETER
 
 fun ubyte(vararg a: UByte) {}

compiler/testData/diagnostics/testsWithUnsignedTypes/explicitUnsignedLongTypeCheck.kt

@@ -1,5 +1,3 @@
-// !LANGUAGE: +InlineClasses
-// !SKIP_METADATA_VERSION_CHECK
 // !DIAGNOSTICS: -UNUSED_PARAMETER
 
 val a0: Int = <!CONSTANT_EXPECTED_TYPE_MISMATCH!>1uL<!>

compiler/testData/diagnostics/testsWithUnsignedTypes/forbiddenEqualsOnUnsignedTypes.kt

@@ -1,5 +1,3 @@
-// !LANGUAGE: +InlineClasses
-// !SKIP_METADATA_VERSION_CHECK
 // !DIAGNOSTICS: -UNUSED_VARIABLE
 
 fun test(

compiler/testData/diagnostics/testsWithUnsignedTypes/overloadResolutionOfBasicOperations.kt

@@ -1,5 +1,3 @@
-// !LANGUAGE: +InlineClasses
-// !SKIP_METADATA_VERSION_CHECK
 // !DIAGNOSTICS: -UNUSED_VARIABLE
 
 fun test() {

compiler/testData/diagnostics/testsWithUnsignedTypes/unsignedLiteralsInsideConstVals.kt

@@ -1,5 +1,3 @@
-// !LANGUAGE: +InlineClasses
-// !SKIP_METADATA_VERSION_CHECK
 
 const val u0 = 1u
 const val u1: UByte = 2u

compiler/testData/diagnostics/testsWithUnsignedTypes/unsignedLiteralsOverflowSignedBorder.kt

@@ -1,5 +1,3 @@
-// !LANGUAGE: +InlineClasses
-// !SKIP_METADATA_VERSION_CHECK
 // !DIAGNOSTICS: -UNUSED_PARAMETER
 
 const val u1: UByte = 0xFFu

compiler/testData/diagnostics/testsWithUnsignedTypes/unsignedLiteralsTypeCheck.kt

@@ -1,5 +1,3 @@
-// !LANGUAGE: +InlineClasses
-// !SKIP_METADATA_VERSION_CHECK
 
 val a0: Any = 1u
 

compiler/testData/diagnostics/testsWithUnsignedTypes/varargTypeToArrayTypeCheck.kt

@@ -1,5 +1,3 @@
-// !LANGUAGE: +InlineClasses
-// !SKIP_METADATA_VERSION_CHECK
 
 fun ubyte(vararg a: UByte): UByteArray = a
 fun ushort(vararg a: UShort): UShortArray = a