Add deprecation warnings for policies CMP0088 and below

The OLD behaviors of all policies are deprecated, but only by
documentation.  Add an explicit deprecation diagnostic for policies
introduced in CMake 3.14 and below to encourage projects to port
away from setting policies to OLD.

Source/cmMakefile.cxx

@@ -4426,13 +4426,12 @@ bool cmMakefile::SetPolicy(cmPolicies::PolicyID id,
     return false;
   }
 
-  // Deprecate old policies, especially those that require a lot
-  // of code to maintain the old behavior.
-  if (status == cmPolicies::OLD && id <= cmPolicies::CMP0081 &&
+  // Deprecate old policies.
+  if (status == cmPolicies::OLD && id <= cmPolicies::CMP0088 &&
       !(this->GetCMakeInstance()->GetIsInTryCompile() &&
         (
           // Policies set by cmCoreTryCompile::TryCompileCode.
-          id == cmPolicies::CMP0065))) {
+          id == cmPolicies::CMP0065 || id == cmPolicies::CMP0083))) {
     this->IssueMessage(MessageType::DEPRECATION_WARNING,
                        cmPolicies::GetPolicyDeprecatedWarning(id));
   }

Tests/RunCMake/GeneratorExpression/CMP0085-OLD-stderr.txt

@@ -0,0 +1,8 @@
+^CMake Deprecation Warning at CMakeLists.txt:[0-9]+ \(cmake_minimum_required\):
+  The OLD behavior for policy CMP0085 will be removed from a future version
+  of CMake.
+
+  The cmake-policies\(7\) manual explains that the OLD behaviors of all
+  policies are deprecated and that a policy should be set to OLD only under
+  specific short-term circumstances.  Projects should be ported to the NEW
+  behavior and not rely on setting a policy to OLD.$

Tests/RunCMake/UseSWIG/CMP0086-OLD-stderr.txt

@@ -0,0 +1,10 @@
+^CMake Deprecation Warning at CMP0086-OLD.cmake:[0-9]+ \(cmake_policy\):
+  The OLD behavior for policy CMP0086 will be removed from a future version
+  of CMake.
+
+  The cmake-policies\(7\) manual explains that the OLD behaviors of all
+  policies are deprecated and that a policy should be set to OLD only under
+  specific short-term circumstances.  Projects should be ported to the NEW
+  behavior and not rely on setting a policy to OLD.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:[0-9]+ \(include\)$

Tests/RunCMake/add_subdirectory/CMP0082-OLD-stderr.txt

@@ -0,0 +1,8 @@
+^CMake Deprecation Warning at CMakeLists.txt:[0-9]+ \(cmake_policy\):
+  The OLD behavior for policy CMP0082 will be removed from a future version
+  of CMake.
+
+  The cmake-policies\(7\) manual explains that the OLD behaviors of all
+  policies are deprecated and that a policy should be set to OLD only under
+  specific short-term circumstances.  Projects should be ported to the NEW
+  behavior and not rely on setting a policy to OLD.$

Tests/RunCMake/find_package/CMP0084-OLD-stderr.txt

@@ -0,0 +1,10 @@
+^CMake Deprecation Warning at CMP0084-OLD.cmake:[0-9]+ \(cmake_policy\):
+  The OLD behavior for policy CMP0084 will be removed from a future version
+  of CMake.
+
+  The cmake-policies\(7\) manual explains that the OLD behaviors of all
+  policies are deprecated and that a policy should be set to OLD only under
+  specific short-term circumstances.  Projects should be ported to the NEW
+  behavior and not rely on setting a policy to OLD.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:[0-9]+ \(include\)$

Tests/RunCMake/install/CMP0087-OLD-stderr.txt

@@ -0,0 +1,8 @@
+^CMake Deprecation Warning at CMP0087-OLD/CMakeLists.txt:5 \(cmake_policy\):
+  The OLD behavior for policy CMP0087 will be removed from a future version
+  of CMake.
+
+  The cmake-policies\(7\) manual explains that the OLD behaviors of all
+  policies are deprecated and that a policy should be set to OLD only under
+  specific short-term circumstances.  Projects should be ported to the NEW
+  behavior and not rely on setting a policy to OLD.$