Fix import resolution for some cases of malformed imports ("import some.")

Fix parsing import directives in case of non-identifier after "import"
Add diagnostics test for malformed imports

compiler/testData/diagnostics/tests/imports/MalformedImports.kt

@@ -0,0 +1,9 @@
+package test
+
+import <!UNRESOLVED_REFERENCE!>some<!>.<!SYNTAX!><!>
+import <!SYNTAX!>.some<!>
+import <!SYNTAX!>.kotlin<!>
+import kotlin.<!SYNTAX!><!>
+import<!SYNTAX!><!>
+import <!SYNTAX!>.<!>
+import <!SYNTAX!>*<!>

compiler/testData/diagnostics/tests/imports/MalformedImports.txt

@@ -0,0 +1,4 @@
+package
+
+package test {
+}