fix(runtime): Throw a native exception in parseType

`parseType` would return a non-initialized result variable which
lead to a crash later when execution continued. Replace it with
an Objective-C exception which rewinds the stack and only after
that becomes converted to a JS exception.

Author: mbektchiev

src/NativeScript/JSErrors.h

@@ -16,6 +16,8 @@
 
 #define NS_EXCEPTION_SCOPE_ZERO_RECURSION_KEY @"__nsExceptionScopeZeroRecursion"
 
+#define NS_THROW(msg) @throw [NSException exceptionWithName:NSGenericException reason:msg userInfo:nil];
+
 #define NS_TRY @try
 
 #define NS_CATCH_THROW_TO_JS(execState)                                                                  \

src/NativeScript/TypeFactory.mm

@@ -101,7 +101,8 @@
 
     const StructMeta* structInfo = static_cast<const StructMeta*>(MetaFile::instance()->globalTableJs()->findMeta(structName.impl()));
     if (!structInfo) {
-        @throw [NSException exceptionWithName:NSGenericException reason:[NSString stringWithFormat:@"Struct \"%s\" is missing from metadata. It may have been blacklisted.", structName.utf8().data()] userInfo:nil];
+        NSString* errorMsg = [NSString stringWithFormat:@"Struct \"%s\" is missing from metadata. It may have been blacklisted.", structName.utf8().data()];
+        NS_THROW(errorMsg);
     }
 
     ffi_type* ffiType = new ffi_type({ .size = 0,
@@ -277,7 +278,7 @@
 
     if (!klass || !metadata) {
         if (strcmp(metadata->name(), "NSObject") == 0) {
-            @throw [NSException exceptionWithName:NSGenericException reason:@"fatal error: NativeScript cannot create constructor for NSObject." userInfo:nil];
+            NS_THROW(@"fatal error: NativeScript cannot create constructor for NSObject.");
         }
 #ifdef DEBUG
         NSLog(@"** Can not create constructor for \"%s\". Casting it to \"NSObject\". **", metadata->name());
@@ -478,9 +479,8 @@
         if (Class klass = objc_getClass(declarationName.utf8().data())) {
             result = globalObject->constructorFor(klass, additionalProtocols);
         } else {
-            auto scope = DECLARE_THROW_SCOPE(execState->vm());
-            WTF::String message = makeString("Class \"", declarationName, "\" referenced by type encoding not found at runtime.");
-            throwException(execState, scope, JSC::createError(execState, message, defaultSourceAppender));
+            auto errorMsg = [NSString stringWithFormat:@"Class \"%s\" referenced by type encoding not found at runtime.", declarationName.utf8().data()];
+            NS_THROW(errorMsg);
         }
 
         break;