Change format of -X arguments to require value after '='

Report a warning when an argument is passed in the old form (with the
whitespace)

 #KT-17264 Fixed

libraries/stdlib/build.gradle

@@ -101,7 +101,7 @@ compileBuiltinsKotlin {
         freeCompilerArgs = [
                 "-version",
                 "-Xallow-kotlin-package",
-                "-Xdump-declarations-to", "${buildDir}/runtime-declarations.json",
+                "-Xdump-declarations-to=${buildDir}/runtime-declarations.json",
                 "-cp", "${rootDir}/../dist/builtins",
                 "-module-name", "kotlin-runtime"
         ]
@@ -113,7 +113,7 @@ compileKotlin {
                 "-version",
                 "-Xallow-kotlin-package",
                 "-Xmultifile-parts-inherit",
-                "-Xdump-declarations-to", "${buildDir}/stdlib-declarations.json",
+                "-Xdump-declarations-to=${buildDir}/stdlib-declarations.json",
                 "-module-name", project.name
         ]
     }

libraries/stdlib/jre7/build.gradle

@@ -48,7 +48,7 @@ compileKotlin {
     kotlinOptions.freeCompilerArgs = [
             "-Xallow-kotlin-package",
             "-Xmultifile-parts-inherit",
-            "-Xdump-declarations-to", "${buildDir}/stdlib-jre7-declarations.json",
+            "-Xdump-declarations-to=${buildDir}/stdlib-jre7-declarations.json",
             "-module-name", project.name
     ]
 }

libraries/stdlib/jre8/build.gradle

@@ -50,7 +50,7 @@ compileKotlin {
     kotlinOptions.freeCompilerArgs = [
             "-Xallow-kotlin-package",
             "-Xmultifile-parts-inherit",
-            "-Xdump-declarations-to", "${buildDir}/stdlib-jre8-declarations.json",
+            "-Xdump-declarations-to=${buildDir}/stdlib-jre8-declarations.json",
             "-module-name", project.name
     ]
 }