Move forbidden api signature files to dev-tools.

This avoids the files showing up in the binary release, since .txt files
are copied.

closes #7917
closes #7921

Author: rjernst

all-signatures.txt renamed to dev-tools/forbidden/all-signatures.txt

@@ -1213,8 +1213,8 @@
                                 <bundledSignature>jdk-system-out</bundledSignature>
                             </bundledSignatures>
                             <signaturesFiles>
-                                <signaturesFile>core-signatures.txt</signaturesFile>
-                                <signaturesFile>all-signatures.txt</signaturesFile>
+                                <signaturesFile>dev-tools/forbidden/core-signatures.txt</signaturesFile>
+                                <signaturesFile>dev-tools/forbidden/all-signatures.txt</signaturesFile>
                             </signaturesFiles>
                             <signatures>${forbidden.signatures}</signatures>
                         </configuration>
@@ -1242,8 +1242,8 @@
                                 <!-- end exclude for GC simulation  -->
                             </excludes>
                             <signaturesFiles>
-                                <signaturesFile>test-signatures.txt</signaturesFile>
-                                <signaturesFile>all-signatures.txt</signaturesFile>
+                                <signaturesFile>dev-tools/forbidden/test-signatures.txt</signaturesFile>
+                                <signaturesFile>dev-tools/forbidden/all-signatures.txt</signaturesFile>
                             </signaturesFiles>
                             <signatures>${forbidden.test.signatures}</signatures>
                         </configuration>