[test] Move tests that only test the Frontend out of Driver/

Reorganization only.

Author: jrose-apple

test/Driver/Inputs/lib.swift

@@ -1,3 +1,3 @@
-// Used by multiple_input.swift and emit-objc-header.swift tests.
+// Used by emit-objc-header.swift and others.
 
 func libraryFunction() {}

test/Driver/Inputs/main.swift

@@ -1,5 +1,5 @@
-// Used by multiple_input.swift and emit-objc-header.swift tests. This file
-// should be inferred as the main source file from its name.
+// Used by emit-objc-header.swift and others.
+// This file should be inferred as the main source file from its name.
 
 var x = 4 + 5
 print(x)

test/Driver/multiple_input.swift

@@ -0,0 +1 @@
+func libraryFunction() {}

test/Driver/Inputs/bad_output_filemap.yaml renamed to test/Frontend/Inputs/bad_output_filemap.yaml

@@ -0,0 +1,8 @@
+// This file should be inferred as the main source file from its name.
+
+var x = 4 + 5
+print(x)
+
+// Check implicit visibility.
+libraryFunction()
+ThisModule.libraryFunction()

test/Frontend/Inputs/multiple_input/lib.swift

@@ -0,0 +1,6 @@
+// RUN: %target-swift-frontend -typecheck %S/Inputs/multiple_input/main.swift %S/Inputs/multiple_input/lib.swift %s -module-name ThisModule
+// RUN: %target-swift-frontend -typecheck %s %S/Inputs/multiple_input/lib.swift %S/Inputs/multiple_input/main.swift -module-name ThisModule
+
+// RUN: not %target-swift-frontend -typecheck -parse-as-library %S/Inputs/multiple_input/main.swift %S/Inputs/multiple_input/lib.swift %s 2>&1 | %FileCheck %s
+// CHECK: main.swift:
+// CHECK: expressions are not allowed at the top level