C++: Replace import default with import cpp

Some tests still used the old name for the top-level library.

cpp/ql/test/header-variant-tests/deduplication/classes.ql

@@ -1,4 +1,4 @@
-import default
+import cpp
 
 from Class c, string n
 where n = count(Class x | x.getName() = c.getName()) + " distinct class(es) called " + c.getName()

cpp/ql/test/library-tests/allocators/allocators.ql

@@ -1,4 +1,4 @@
-import default
+import cpp
 import semmle.code.cpp.models.implementations.Allocation
 
 query predicate newExprs(

cpp/ql/test/library-tests/conversions/conversions.ql

@@ -1,4 +1,4 @@
-import default
+import cpp
 
 string getValueCategoryString(Expr expr) {
   if expr.isLValueCategory()

cpp/ql/test/library-tests/ir/constant_func/constant_func.ql

@@ -1,4 +1,4 @@
-import default
+import cpp
 import semmle.code.cpp.ir.IR
 import semmle.code.cpp.ir.implementation.aliased_ssa.constant.ConstantAnalysis
 import semmle.code.cpp.ir.internal.IntegerConstant

cpp/ql/test/library-tests/ir/escape/escape.ql

@@ -1,4 +1,4 @@
-import default
+import cpp
 import semmle.code.cpp.ir.implementation.unaliased_ssa.internal.AliasAnalysis
 import semmle.code.cpp.ir.implementation.raw.IR
 import semmle.code.cpp.ir.implementation.UseSoundEscapeAnalysis

cpp/ql/test/library-tests/ir/escape/ssa_escape.ql

@@ -1,4 +1,4 @@
-import default
+import cpp
 import semmle.code.cpp.ir.implementation.aliased_ssa.internal.AliasAnalysis
 import semmle.code.cpp.ir.implementation.aliased_ssa.internal.AliasConfiguration
 import semmle.code.cpp.ir.implementation.unaliased_ssa.IR

cpp/ql/test/library-tests/literals/uuidof/uuidof.ql

@@ -1,4 +1,4 @@
-import default
+import cpp
 
 query predicate classUuids(Class cls, string uuid) {
   if exists(cls.getUuid()) then uuid = cls.getUuid() else uuid = ""