C++: Add a test of charLoc and subsumes.

Author: geoffw0

cpp/ql/test/library-tests/locations/charloc/charloc.cpp

@@ -0,0 +1,8 @@
+
+void test()
+{
+  1;
+  2 + 3;
+          (
+4);
+}

cpp/ql/test/library-tests/locations/charloc/charloc.expected

@@ -0,0 +1,6 @@
+| charloc.cpp | 1 | 39 | 39 | 1 |
+| charloc.cpp | 2 | 48 | 48 | 2 |
+| charloc.cpp | 3 | 52 | 52 | 3 |
+| charloc.cpp | 4 | 64 | 64 | 4 |
+| charloc.cpp | (...) | 65 | 65 | (...) |
+| charloc.cpp | ... + ... | 48 | 52 | ... + ..., 2, 3 |

cpp/ql/test/library-tests/locations/charloc/charloc.ql

@@ -0,0 +1,7 @@
+import cpp
+
+from File f, Expr e, Location l, int start, int end
+where
+  e.getLocation() = l and
+  l.charLoc(f, start, end)
+select f.getBaseName(), e.toString(), start, end, concat(Expr e2, Location l2 | e2.getLocation() = l2 and l.subsumes(l2) | e2.toString(), ", ")